It's one of London's busiest streets where hordes of bustling executives on six-figure salaries race past to catch their trains back to the Home Counties every day.
But while countless numbers of those passengers will pop into the nearby bars and restaurants for post-work refreshment, for the scruffily dressed man sitting on the pavement subsistence is the furthest thing from his mind.
Instead he appears intent on filling the stubby pipe he is holding, carefully sliding the contents of a paper wrap into its business end, tamping it down and then fumbling to find a lighter to ignite his workings before inhaling deeply – and then slumping over, now barely conscious.
The footage of this sordid moment on London's Victoria Street was filmed in the early evening this week when the area was teeming with life.
Welcome to the grim new reality of London's druggy underbelly, where the new substance of choice is the synthetic cannabinoid known by the street name Spice.
The class-B drug, notorious for turning users almost instantly into so-called 'zombies', was originally synonymous with the socially troubled inner cities of the US, before arriving in Europe as the drug of choice in Britain's prisons.
Spice is the new substance of choice for many of London's rough sleepers, a class-B drug notorious for turning users almost instantly into so-called 'zombies'
In central London, Spice is used regularly by rough sleepers and can be purchased for as little as £3
At Grosvenor Gardens, a mixed group of male and female rough sleepers were spotted climbing over the fence after closing hours to use the benches within as a drug den (Pictured: Unidentified sleepers near Lower Grosvenor Gardens)
And the reason is that despite its potency, enough Spice for a pipe like that we saw being consumed in London's commuter district can be purchased for as little as £3.
On patrol around Westminster this week we saw it being used widely.
In nearby Grosvenor Gardens, for instance, we witnessed a mixed group of male and female rough sleepers climb over the fence after closing hours to use the benches within as a drug den.
Once inside, they loaded similar-looking pipes and took turns smoking from it.
Almost immediately one man was hunched over, seemingly unable to move, as the effects of the drug took hold.
Further on we saw two men slumped in a pub doorway after an apparent hit, while two others paced about slowly as though possessed – the manner of which has led to the zombie-like comparison.
Many of those in the grip of the problem are strongly resistant to attempts to help them and will often respond angrily or simply back away from offers of a secure and clean bed for the night.
Claire Dunn, from public protection at Westminster Council, said the problem with Spice is exacerbated by the fact that it's so extraordinarily cheap – less than a cup of coffee.
'People can get a small amount for around £3,' she said. 'And if there's a group of them and they can muster £30 they can often buy it more cheaply still because dealers will sell larger quantities for less.
'That means the supply-and-demand cycle just perpetuates itself.'
The effects can be horrific, she says.
'You see people slumped on the floor. They have been sick on themselves. Sometimes we have seen people who have urinated or defecated on themselves because they have lost control of their bodily functions.
'Sometimes people look as though they are not breathing. They are not moving and they are not communicating.'
The Daily Mail joined Westminster Council members, enforcement specialists and outreach workers on a walk through Victoria to see the problem first-hand.
Even before the patrol began, the scale of the challenge was impossible to miss.
A woman was spotted squatting against the side of Westminster City Hall, using the council's own headquarters as a toilet before wandering away in an apparent daze.
Just yards away, another rough sleeper was dozing in a tent directly outside the building.
'When you don't tackle things quickly, they fester,' Councillor Caroline Sargent, Westminster's deputy leader and cabinet member for enforcement. 'That is why we are trying to do something about this.'
Ms Sargent said Conservative-run Westminster is trying to tackle homelessness but often encounters reluctance from the very people they are trying to help.
She said: 'Around Victoria, for example, there is a cohort of people with very complex needs, often involving addiction, who have been offered a great deal of support.
'Some repeatedly refuse that support and remain on the street, where we see antisocial behaviour including public defecation, urination and open drug use.
'That has a real impact on residents and businesses.
'What we want people to understand is that this is not always simply a homelessness problem. Some of the people involved actually have accommodation available to them, including hostel places.'
As the patrol moved towards nearby Grosvenor Gardens, several men were slumped against a wall appearing to smoke drugs.
Council enforcement officers approached to check what was happening and one of them threw their paraphernalia over the fence into locked gardens.
The problem with Spice, according to a representative from Westminster Council, is its low price - with it costing less than a cup of coffee
One rough sleeper, 31, originally from Bedford, gave a harrowing account of his experience as a Spice user.
He told us: 'When I can't even muster a few quid I've often sat on the pavement scavenging up bits of Spice and ash just so I can smoke whatever is left. That's how desperate it gets.
'I've been so desperate for it that dignity just disappears. You'll beg, borrow, search the floor, whatever it takes.
'Every time you take it, it can be different. Sometimes it feels amazing but it can also be horrible. I have seen spiders everywhere, or heard voices, or thought I was going to die.
'I developed a nervous tic after using it. My speech also started to go.
'You start telling yourself "This is the last one" – but then an hour later you're trying to find money for another hit.
'I've used heroin before as well, and Spice can be just as hard to off as that is – you tell yourself you're going to stop, but then you wake up and you're looking for it again.'
Councillors say Spice is frequently adulterated with other substances – creating 'Frankenstein' concoctions so users may have little idea what they are actually taking.
Supplying the addicts often involves a growing number of naive and exploited young people, referred to as 'runners'.
Ms Dunn said: 'They are usually young people from disadvantaged backgrounds who are told, "Take this, sell £500 worth and we'll give you £50".
'We have had a number of them arrested over the last six months and by the very next day there is a new runner out on the street.
'For these kids it looks like easy money, but they are being targeted and exploited.'
In one recent case, she said, a 17-year-old boy was found with around 50 wraps of heroin and cocaine in his mouth when stopped by police.
From Grosvenor Gardens, the patrol continued towards Westminster Cathedral where a soup kitchen is run and around a dozen homeless people have gathered to eat.
But Cllr Sargent said even well-meaning initiatives like this can create unintended problems.
'While people understandably think they are doing something kind by handing out food and hot meals, many of the people coming here need far more help than that.
'They have complex health needs and addictions.
'It can also bring people together in one place and, unfortunately, that can attract drug dealers as well.'
One rough sleeper, Paola, 49, said she herself avoids Victoria at night because of the danger posed by other homeless people and dealers.
She said: 'I come here to eat. But I never stay overnight. It's too dangerous.'
Cllr Sargent said Westminster wanted a tougher response where persistent antisocial behaviour followed offers of support – and the next recourse should be police action.
But officer numbers, she said, were a major problem.
Paola, who has been rough sleeping for four years, said she leaves Victoria at night because of the danger posed by other homeless people and dealers
It is thought Spice is now a bigger draw for many rough sleepers than physical comfort and security
'Last summer, when things became particularly difficult, some charities felt they could not properly do their jobs because their own outreach workers did not feel safe,' she said.
'Having a police presence makes a huge difference. The problem is that there simply are not enough officers.'
Councillor David Harvey echoed the fears, saying local officers are often pulled away to demonstrations and other duties.
'We have some really good officers, but only a tiny number of them,' he said.
'I think quite often the police have not felt backed. Officers can feel that if they take a more assertive approach towards disruptive homeless people, they may end up getting into trouble for it.'
The council itself has much more limited powers.
Despite the outrage of many Londoners, its enforcement officers cannot simply physically remove somebody from the pavement.
'People have to remember that council officers are not police officers,' Cllr Sargent said.
'The police can physically detain somebody and arrest them if necessary. Council officers cannot simply pick someone up and remove them.'
The legal backdrop has also shifted following the repeal of the 200-year-old Vagrancy Act in June, ending the old blanket criminalisation of rough sleeping and begging in favour of more targeted powers aimed at harmful behaviour.
Meanwhile, Councillor Festus Akinbusoye, deputy cabinet member for enforcement and a former Bedfordshire Police and Crime Commissioner, told of a visiting professor friend from California who had been shocked by the amount of visible drug use in London.
Westminster Council recorded 293 rough sleepers across the borough in their latest count. In Victoria alone, 61 people were marked as homeless
The comparison was particularly striking given the notorious scenes of open drug addiction in cities such as San Francisco.
He said: 'It's just really sad, you know, the case of homelessness in general.'
The council's latest September count recorded 293 rough sleepers across the borough – 6 per cent fewer than at the same time last year.
In Victoria alone, 61 people were recorded. Of those, 48 were identified and engaged with outreach teams, while 13 – more than one in five – were unidentified or would not engage. Five were already subject to enforcement action, the council said.
Council officials estimate that between 10 and 20 per cent of rough sleepers approached by outreach teams will reject the help being offered.
Spice is now a bigger draw for many of them than physical comfort and security, it seems.
The Mayor's Office was contacted for comment.