A former Metropolitan police commissioner has waded into the political row about the impact of austerity by warning that potential terrorist tip-offs are being missed because of cuts in police numbers.

Paul Condon, who headed the Met from 1993 to 2000, said the reduction in the number of frontline officers had left the police close to breaking point.

Since 2010, when Theresa May became home secretary, the number of police officers has decreased by 20,000. In an interview with BBC Radio 4’s Today programme, Lord Condon did not mention the prime minister, but he did cite this figure, which has become most associated with her watch as home secretary.

“You can’t take out 20,000 street cops and 20,000 support staff and maintain all the contacts with the community which you give you the leads,” he warned.

Condon suggested the cuts could lead to the police missing vital information about future terrorist attacks. “The security services and the police have been brilliant in foiling plot after plot after plot, but as we know the terrorists only have to get successful once and police forces up and down the country are stretched. They don’t have the numbers in the community where day-to-day they can be picking up the sort of street intelligence they want.”

Condon said there was no capacity to cut police budgets any further, saying: “They are doing an incredibly good job but they are stretched almost to breaking point. I have real anxieties about the resources. Certainly I don’t think they can take more operational cuts short term and they are under enormous pressure.”

He added: “I think they are right at the sort of edge of what is practical in terms of the sources they have available.”

Condon is the latest senior former police officer to warn that austerity is making the UK more vulnerable to attack. Last month, Robert Quick, who led the counter-terrorism effort from 2008 to 2009, told the Guardian that intelligence from communities about people supporting violent jihad had been lost because of cuts.

He said: “Counter-terrorism funding is ringfenced but cuts to the general policing budget [have] impacted on neighbourhood policing teams in many parts of the country including London. This has reduced the capacity of the police to work in communities building relationships and trust to in turn generate community-based intelligence about persons of concern.”

Last week, the Met revealed it had sold off almost £1bn-worth of London property over the past five years in an attempt to make multimillion pound savings.

A spokesman for the Home Office said the government had protected police funding in real terms and was talking to senior officers about the resources they need.