The NHS faces a 'make or break' financial crisis within two years unless the Government orders an immediate multibillion pound cash injection, former health minister and North Norfolk MP Norman Lamb has claimed.

In a bleak assessment Mr Lamb, a key figure in the Department of Health during the coalition era as Liberal Democrat care services minister, suggests that the NHS is on course for a 'crash'.

Pre-election promises by the Tories to provide an additional £8 billion for the health service by 2020, on top of £2 billion extra pledged at the end of last year, will not be enough, he told the Observer.

Suggesting that the promised money needed to enter the system before 2020 he said: 'If the investment is not made upfront and in the early period of this parliament, you could see serious failures in the system.'

Warning of the consequences he said: 'The system will crash. Elderly people won't get the care they need, and it will be people with mental ill health who suffer most, because that is where the squeeze always comes.'

As well as the timing of the extra funding, Mr Lamb also questioned the amount of money pledged.

He said: 'I don't think anyone in the NHS believes that is enough. The Government talks very vaguely about an extra £8bn by 2020, but it is needed now.

'If it comes in 2019-20, the system will have crashed by then. I think the next two years will make or break the NHS and the care system.'

Mr Lamb's comments come after Health Secretary Jeremy Hunt told MPs last week 'the financial pressures on the NHS are the worst that they have ever been in its history'.

A Department of Health spokeswoman said: 'We are investing the additional £8 billion that the NHS itself has said it needs to implement its own plan for the future.

'The NHS must deliver its side of the plan by implementing cost-control initiatives the Government has brought forward, like clamping down on staffing agencies and expensive management consultants.

'We're already bringing the NHS and councils together, which is helping people to live independently at home and saving money in the long term.'