Middle-aged men will no longer be entitled to tests to help detect prostate cancer.

New guidance means men over 50 can no longer access blood tests which help to find the disease and GPs will have the power to decide who can take one.

Former Prime Minister Lord Cameron, who was treated for the disease after taking a test, said the move was a ‘backwards step’.

Until the most recent guidance, any man aged over 50 has had access to a prostate-specific antigen (PSA) test through their GP and did not need to have symptoms.

But now doctors will make the final decision on whether or not a test is needed.

The change follows the Government’s decision not to roll out widespread prostate cancer screening and instead use more targeted testing for high-risk groups.

The new guidance was sent in a letter to health organisations on Thursday and was seen by The Daily Telegraph. 

It has been criticised by Prostate Cancer Research as a 'shocking betrayal and backward step that will condemn thousands more men each year to a late and incurable diagnosis'. 

Several high-profile prostate cancer diagnoses in middle-aged men, including Sir Chris Hoy and Jeremy Clarkson have increased demands for PSA tests. 

David Cameron revealed that he was diagnosed with prostate cancer last year.

The decision to row back the testing was made by officials at the Department of Health and Social Care (DHSC) without public consultation. 

The letter said: 'The prostate cancer risk management programme guidance has been withdrawn.' 

It continued: 'A patient is worried about prostate cancer, then they can ask their GP about having a PSA test. 

'As the health professional, the GP will consider the patient’s cancer risk to help with reaching a judgment on whether undertaking a PSA test is the right option for the patient, whilst clearly laying out to the patient the pros and cons associated with doing so.' 

The letter also said that the latest guidance no longer considers men over 50 to be at high risk, because age is just one factor in assessing risk, despite the fact that the chance of disease rises with age. 

Lord Cameron told The Telegraph: 'This is yet another step backwards and once again shows why we need simple, proper targeted screening for all at-risk men.

'Screening is essential to catch cancers early, when they can be more effectively and successfully treated. Only due to testing, my cancer was caught and treated in time.

'I urge the new Prime Minister and Health Secretary to be brave and bold. Stop the complexity and confusion and introduce a more progressive and life-saving policy: a proper, targeted screening programme that involves all those at higher risk.

'Without it, more men will die, and more families will lose a loved one. Heed the warnings, this is avoidable and can be done.' 

Prostate cancer is the most common cancer in men in the UK, with around 63,000 diagnoses and 12,000 deaths annually. 

The Daily Mail has long campaigned for improved prostate cancer diagnosis and treatment to end needless deaths from the disease. 

Meanwhile, thousands of men suffering with prostate cancer are being denied access to a 'quality of life-preserving' treatment by the NHS.

Focal therapy, a non-invasive treatment which targets cancerous cells while avoiding damaging surrounding tissue, was introduced to the UK in 2006.

The treatment dramatically reduces the risk of incontinence and erectile dysfunction, side effects which can affect up to 20 per cent of men who undergo other forms of cancer treatment such as radiotherapy.

It is also much cheaper than other treatments, with patients usually in and out of hospital in a day and less likely to need follow-up care.

But it is still rarely available on the NHS despite around 15,000 men who could benefit.

While tens of thousands of men are diagnosed with prostate cancer each year, a mere 600 to 700 are thought to be offered the treatment, although it is widely available privately for an average £16,000.

David Cameron paid to be privately treated with focal therapy after he was diagnosed with prostate cancer.

The former Prime Minister was diagnosed after his wife Samantha urged him to get a PSA having listened to a radio interview on symptoms.

Focal therapy is just as effective as surgery, according to a study published by Imperial College London.

Top Gear and Mr Clarkson's Farm fans were devastated to find out Mr Clarkson was diagnosed with the cancer this summer. 

The Grand Tour star revealed on his TV show Mr Clarkson's Farm in June that he had been diagnosed with 'aggressive' prostate cancer in May last year but it was caught early, and he has since shared he's in remission. 

Mr Clarkson secretly underwent HIFU (high-intensity focused ultrasound) to target the tumour before announcing his diagnosis. 

The former Top Gear presenter went public with his health crisis during series five of Clarkson's Farm and he's admitted he only shared the details because his treatment meant he would have to miss a lot of filming.

At the end of the final episode, Mr Clarkson was seen lying in a hospital bed after being rushed to hospital and he's now revealed it came after he restarted blood-thinning medication for his heart problems.

A malignant tumour was found in his prostate in August, leading to the secret operation right in the middle of his harvest.

'It was an aggressive type of cancer,' he said. 'It could have spread, it could have gone into the pancreas... and that would have been trouble.'

Now he's using his own experience to deliver a blunt message: 'This is why I have to say to everybody who's reading this, please, please, please go and get checked.

'It's not uncomfortable, it's not undignified. And it's a no-brainer. I did, and that's why I'm sitting here talking to you 11 months down the line.'

Jeremy has highlighted how his early diagnosis after getting checked has been pivotal in treating the cancer. 

A spokesman for the health department said: 'Every man still has the right to ask their GP for a PSA test and it remains the case that the final decision rests with GPs.'