Charlotte and Damien Hall are teetotal non-smokers with a stable 11-year marriage behind them. She has a career as a nanny and he shares her love of children. They would appear to be ideal candidates as adopters for a child in need of a new family.

But yesterday it emerged that Leeds city council has rejected the Halls - because he is too fat. The couple had approached the authority about adoption but after health checks were informed his 6ft 1in (1.8 metre), 24.5 stone (156kg) physique gave him a body mass index of 42, categorised as morbidly obese and at increased risk of serious illness or death. The couple were told that if his BMI dropped below 40 and he was able to maintain the weight loss, they would be reconsidered.

The Halls are shocked by the decision and yesterday Mr Hall insisted his weight did not mean he could not provide a child with a healthy domestic environment.

"It's hard to lose weight under pressure," the 37-year-old call centre worker said. "I'm not a couch potato and I don't sit eating takeaways every night. I just feel as though we were only judged on my weight and not all the other good things about us. We don't drink or smoke and we could give a child a safe and happy home. I'm 24.5 stone, that's what it eventually comes down to. Everything stops because of one element.

"We don't know whether there would be any other blocking factors or any other considerations to be made. It is difficult to put into words the emotional desire to have kids, especially when you are not allowed because of your weight." Being given advice to eat more healthily was "kind of insulting".

In a letter the local authority told the Halls: "We are unable to progress an application from you at this time. This is due to the concerns that the medical advisers have expressed regarding Mr Hall's weight. We will require Mr Hall to have a further medical in six months' time, which will be considered by our medical adviser."

It added that the adoption panel was unlikely to approve applicants with a BMI over 40 because of the long-term health risks. "It would therefore be to your advantage to begin the assessment with an up to date medical where your BMI is clearly recorded as being under 40 and to demonstrate that you are able to maintain this weight loss over the period of the assessment."

Charlotte Hall, 31, said: "We had an inkling they'd say something about weight - but to be turned down flatly just on that, it's just harsh. My husband has a full-time job and is very active. He walks our dog at least twice a day and doesn't feel unfit or unwell.

"You've got a child in care who's going to get up tomorrow morning not knowing where it's going and we're here ready to take a child on. They seem to be saying it's better for them to be in care and being shoved from pillar to post just in case Damien dies." The Department for Children, Schools and Families said it did not issue local authorities with guidance on maximum weight for potential adopters.

Leeds council said the Halls' application was still active and insisted the couple had not been turned down but had been given advice on how to proceed.

A spokeswoman said: "The council's adoption service has a legal responsibility to ensure that its looked-after children are placed with adopters who are able to provide the best possible lifelong care. Part of this responsibility is advice for applicants on a range of suitability criteria, including any health or lifestyle issues which may impact on an applicant's long-term ability to adopt.

"Expert advice on health and medical issues for applicants is provided by medical advisers to the council's adoption service, in line with BAAF [British Association for Adoption and Fostering] guidance."

Mo O'Reilly, director of child placement at the BAAF, said: "Children who are being placed for adoption are by definition already separated from their birth parents. In placing them with a family, as part of the scrutiny it will make sure the child is safe and well looked after to adulthood and beyond."

She said it was important to look at the parents' medical needs so as not to rob a child of another parent. "There is nothing in legislation that says anyone with a BMI over 40 will not be actively considered," O'Reilly said. The only criterion for adopters is that they be over 21. Adoption agencies do take the advice of medical officers after health checks. "They are trying to minimise the risk of putting a child through a situation where they would experience another loss."