By Karen Allen
BBC health correspondent
Telephone help lines will deal with many patients
From tomorrow, the way the NHS operates at the evenings and weekends will change as GPs lose the responsibility to provide 24-hour care.
Instead primary care trusts, which oversee GP services, will have to find new ways of ensuring patients can be cared for out-of-hours.
This could mean patients could be looked after by a GP paid by the Primary Care Trust, or by a nurse. They are also much more likely to be dealt with over the phone.
Doctors will benefit by not having to work anti-social hours - and being paid an market hourly rate if they do, which the government hopes will help attract more into general practice.
But there are warnings that the NHS may not be able to cope with the changes, and that they could leave parts of the health service saddled with debt.
The city of Peterborough is seen as one of the flagship primary care trusts that has spent months preparing it's staff for the change.
But some GPs there fear other areas may not be able to cope so well, and staff shortages may lead to big gaps in service
GP Dr Malcolm Bishop says: "I do have some worries for areas where recruitment is more difficult - and I think they are going to struggle.
"And asking nurses to take on the job again assumes again that there is an inexhaustible supply."
Dr Bishop said any nurses who staffed help lines for patients would have to be specially trained.
Health managers in Peterborough predict they'll handle half of all night calls via a telephone helpline where nurses could either advise patients over the phone, or refer them to its specialist walk-in centre
Only the sickest and the most frail will receive a visit at home - and it may be from a nurse rather than a GP.
Manager Chris Town says the changes are not about cutting costs, but about using doctors and nurses more appropriately.
He said: "We do know there are lots of trained nurses out there who are not working. Sometimes that's because of family commitments, and some of the hours we're talking about can actually be quite convenient.
"It may be that this offers an opportunity to bring people back into nursing."
But not all areas have the same range of trained staff as Peterborough so GPs will be urged to fill the gaps earning premium rates of pay in areas where supply is short.
For some GPs, that could mean an extra £140,000 a year.
PCT's will take on the responsibility for out of hours care. They have between now and the end of the year to recruit and train staff in the same way they've done in Peterborough.
'Too little too late'
Whilst many PCTs have plans in place Dr Gill Morgan from the NHS Confederation believes some will struggle.
Already many have had little option but to sign up to pricey fixed term contracts with GP co-operatives, potentially leaving them with crippling debts.
She warned: "The problem for PCTs is that it's going to be an expensive option.
"It may therefore make it harder for them to develop alternatives as quickly as we would like."
And some fear casualty departments will be inundated with patients who do not know where else to go.
Dr John Heyworth, president of the Association of Accident and Emergency Medicine, said: "Our worry is that too little is being done too late.
"And unless really rather urgent discussions are set up straight away, and the issues are addressed, the public will end up not knowing where to go - and inevitably they will end up coming to the emergency departments."
But Sir Nigel Crisp, chief executive of the NHS, said the change had been planned over four years, and that it was being phased in gradually up to December.
He said the government had invested around £200m
He added: "For the patient it shouldn't be different. The patient will still ring their GP surgery, but behind the scenes you will see a slightly different system.
"And we will be able to get the most appropriate care for people."
Sir Nigel said it appeared the changes were helping to attract more doctors into general practice.