When Awais Akram answered his mobile to Sadia Khatoon, a 24-year-old married woman whom he had met on Facebook and had recently started a physical, but not sexual, relationship with, he had little idea of the fate that was about to befall him.
Mrs Khatoon insisted they meet outside his flat in Leytonstone, east London, but as Mr Akram stepped out into the summer sunshine his lover was nowhere to be seen. Instead he was confronted by three masked men wearing gloves, one of whom was carrying a bottle of "Give It One Shot" drain cleaner.
The men, who included Mrs Khatoon's brother Mohammed Vakas, had come to wipe off what they believed was a stain on their family's "izzat" (honour). Beating and stabbing Mr Akram was not enough. As he lay bleeding on the floor, Vakas stepped over his victim and poured the entire bottle of drain cleaner over Mr Akram's face and body.
In parts of the developing world – particularly south-east Asia, the south Asian subcontinent and east Africa – acid attacks are common. The Taliban and fellow extremists have frequently resorted to throwing acid in women's faces for even small transgressions, such as daring to go out unveiled. But there are concerns that such attacks may also be on the increase in the UK.
Hospital admission figures for the past three years show a steady rise in the number of people being treated for acid attacks. According to the NHS information centre, 44 people were admitted to hospital in 2006-07 after they were "assaulted with a corrosive substance". The following year the figure jumped to 67 and last year there were 69 admissions.
The figures only include hospital admissions where a patient had to spend one night or more in hospital and there is no ethnic breakdown. But charity workers fear there is enough anecdotal evidence to suggest acid attacks are becoming more common.
Acid Survivors Trust International, a charity which specialises in helping victims of acid attacks in places like Bangladesh and Pakistan, recently began work on a project documenting such attacks in Britain. It is the first serious attempt to map where acid assaults take place and what motivates their British perpetrators.
Rick Trask, the charity's UK-based researcher, said it would be some time before they really knew whether acid attacks were an increasing problem but that enough evidence existed to warrant an initial investigation.
"It's hard to pin down exact numbers because they are held across different departments, such as NHS trusts and police," he said. "The question we need to ask is whether the few cases we know about are the tip of the iceberg."
Last week Mr Akram, a Danish-born Muslim of Pakistani origin, relived his ordeal in court during the trial of his attackers, who were jailed for between eight and 30 years. From the witness box, livid scars from the attack last July were clear for all to see. His body suffered 47 per cent burns and needed four skin grafts to repair. In his victim statement, the 25-year-old described how he faced a lifetime of recovery.
"If I ever go out by myself, I get very upset," he said. "I have been out only once or twice. I'm very scared and I keep looking back to see if someone's there. Whenever I do anything my hands don't work properly at the moment. I feel like I have a kind of fear which is inside my brain and I feel like it will be there for the rest of my life."
Mr Trask was keen to highlight that acid attacks happen across a range of different countries, cultures and religions. "You get attacks in Buddhist Cambodia, among Christians in Uganda and across south Asia, which has many different religions," he said. "It's not specific to one culture or another. But what they almost always do have in common is some sort of gender-based violence and the desire to permanently disfigure their victims."
In March 2008 an up-and-coming TV presenter had acid thrown in her face by a man who had been paid by her jilted ex-lover. Katie Piper, now 27, documented her slow and painful recovery in a Channel 4 programme.
Diana Nammi, the founder of the London-based Iranian and Kurdish Women's Rights Organisation, which has helped scores of victims to escape potential honour killings in the UK said: "In Turkey, Kurdistan and Iran [acid attacks are] a very common way of punishing women for what a community deems to be inappropriate or shameful behaviour. What scares me is that there are early indications [they are] becoming more prevalent in Britain."
Miss Nammi said that attackers were motivated by a cruel desire to mark their victims forever and send a terrifying message to the wider community that "cultural transgressions" would not be tolerated.
"It's a way of marking victims with what they believe is a physical manifestation of their shame," she said. "They deliberately take away a person's beauty and mark them forever. In Britain attacks are thankfully quite rare but threats are all too common."
Jasvinder Sanghera, who runs Karma Nirvana, a Derby-based charity that hosts a national helpline for victims of forced marriages and honour violence, agrees.
"We've received many calls from terrified people, usually women, who say a brother or father has threatened to throw acid in their face because of the way they are behaving," she said. "They've seen what happens in Pakistan, or India or Bangladesh, and they know that such a threat could be easily be carried out."