In March, Michael Franciosy vowed to quit for good so he could undergo surgery and become a donor to his 24-year-old son, also called Michael.

He is due to go to Newcastle's Freeman Hospital, which specialises in organ transplants, next week to see a consultant.

"I don't know what's happening after that. It's long and drawn out," said Michael, 47, who added that he was "doing well" at stubbing out the cigarettes.

Michael jnr, of Fordfield Road, Pennywell, has been told he will need a new kidney as his own are functioning at just 25 per cent.

Tests have confirmed that father and son are a perfect match, but doctors told Michael snr he would have to cut out his heavy smoking so he would have a good chance of recovering from the operation.

Michael jnr said: "I'm proud that my dad's come forward. He could die on the table because of his age. He's a real hero.

"I'm chuffed to bits because I'll get my kidney much quicker. It's hard to get a match."

Michael, who also has an appointment at the Freeman Hospital next week, said: "They don't want to put me on dialysis because I'm so young. My kidneys are doing overtime at the minute. I'm tired all the time, groggy and I feel sick. I've got to take tablets every day."

His father said: "I want them to get me to the hospital, put me to sleep and get it out. I'm not scared. I want him to have quality of life. He works for a local wholesaler and he's losing a lot of time at work.

"If I get a phone call now I'll go, no questions asked. I know the risks. He can die and I can die. It's as simple as that.

"I've been advised to stop smoking so that I have a quick recovery from the operation. Apparently it can take your body a lot longer to recover if you smoke."

Michael, of Azalea Avenue, Ashbrooke, smoked his first cigarette when he was seven and within three years was buying packs of five Woodbines with his pocket money.

"I could smoke more than 60 a day. It limited me playing with my children in my 20s. Now I'm eating more. I'm feeling a lot better, a lot healthier.

"I'll keep going until I've given up completely and can have the operation to give Michael my kidney."

Michael jnr, who has a three-year-old son with partner Gemma Richardson, 24, said he was now looking forward to a bright future watching his son grow up.