Ryan Wilson was the worst affected of the six volunteers

Drug victim interview

Ryan Wilson, 20, from London, was the most seriously ill of the six men whose heads and bodies swelled up following injections of TGN1412 in March.

Mr Wilson, who has left hospital, spoke of his anger at the companies involved, during an exclusive BBC interview.

He may lose all of his toes and parts of three fingers.

I'm not a weak person, and anyone who knows me knows that, so I'm not going to give up yet

Ryan Wilson

Mr Wilson is currently using a wheelchair, but will undergoing further surgery in about a month's time.

He said: "I can walk small bits now, but that is only heel-bearing and I have to wear these 'funky' shoes - they do the job, but they are horrid looking.

"Once I have surgery, it [walking] will depend on how long I take to do it - it could be a month, it just depends on determination."

Uncertain future

He adds that doctors are still unsure of the long-term damage that has been caused.

"There are a few parts of the immune system that are not right and they don't know if they will get back to normal, level off or decrease even more. It is hard to tell."

Mr Wilson entered the trial that took place at Northwick Park Hospital to pay for driving lessons.

He and five other volunteers were paid £2,000 to be given TGN1412, created by German pharmaceutical company TeGenero, by medical research company Parexel.

Mr Wilson will lose parts of some of his fingers

It was hoped that the drug would treat conditions such as rheumatoid arthritis and leukaemia, but the trial went disastrously wrong.

Mr Wilson, the worst affected, suffered heart, liver and kidney failure, pneumonia, and septicaemia.

"I wouldn't want anyone else to go through this - even people that I'd call enemies. It's undignified," he told BBC medical correspondent Fergus Walsh.

He said he is angry with the drug companies involved and that he had been through "four months of hell".

Mr Wilson said he is unsure of his future.

He believes his career as a plumber is over: "I've got no power in my hands and you need all five digits when you are doing plumbing.

"That's out of the window and I don't know what I'm going to do now.

"Basically, that's all I've known since I was 15 - that's five years that have been taken away from me."

But despite these setbacks, he said remains optimistic about the future.

"Every day I wake up is a bright day. It was nearly taken away from me.

"I'm not a weak person, and anyone who knows me knows that, so I'm not going to give up yet."