Ministers too often believe they can predict future security threats to the UK, despite the lessons of history, a powerful group of MPS warn today.

They cautioned David Cameron’s government to rethink as it prepares to unveil next week the results of its Strategic Defence and Security Review (SDSR).

A new report by the Commons Defence Committee warns that the UK should develop versatile Armed Forces capable of adapting to a range of potential crises.

MPs suggested the government’s policy was flawed in assuming “that the probability of potential threats becoming actual ones can reliably be predicted”.

They also warned of 'general vulnerabilities' in the Armed Forces including numbers and gaps in capabilities.

Following the last SDSR in 2010 the Army is in the process of scaling back from 100,000 to 80,000 personnel.

The Prime Minister was forced to pledge earlier this year he could not make more soldiers redundant.

Douglas Chapman, the SNP MP for Dunfermline and West Fife and a member of the committee, said that the report highlighted critical capability issues along with a lack of expertise in Whitehall in identifying threats.

He added: “It is becoming clear, in the current security climate, that the UK Government must focus more on the most fundamental aspects of our defence in order that our defence and security personnel can respond adequately to all emerging threats.

“Put simply, I do not understand how spending up to £167 billion on a weapons system that is of questionable military value in the 21st century is seen as a higher priority than the recruitment and retention of service personnel, identified in the report as a vulnerability, alongside capability gaps like the lack of Maritime Patrol Aircraft.

“I will be making sure these are addressed when the SDSR is announced next week.”

Defence committee chairman Dr Julian Lewis said that there was an “overconfidence in Government that it can reliably predict which threats will transpire. History has proven that this approach does not work.”