Police numbers, including the number of armed police officers, have fallen sharply under Theresa May’s watch first as home secretary between 2010 and 2016 and then as prime minister.

The simple numbers tell the story. In 2010 May as home secretary made the mistake that Margaret Thatcher never made in the 1980s and agreed to a Treasury demand to cut police budgets by 18%.

Over the next five years the number of police officers in England and Wales fell from a peak of 144,353 in 2009 to 122,859 in 2016. At the same time the number of specialist armed police officers has fallen from a peak of 6,796 in 2010 to 5,639 in 2016.

As the graph shows it would appear to be an open and shut case that cuts in police officer numbers have had an impact on the capacity of the police to respond.

May was told in 2010 that in cutting police funding she was making a mistake that Thatcher never made when she instinctively realised that there would come a crucial moment when the country, and her premiership, would depend entirely on the resilience of the thin blue line.

May took a different approach as home secretary that was not without foundation. She argued that with the big continuing falls in crime that had been seen since the mid-1990s it was not necessary to maintain such a large police force. Anyway, it was argued, there was no direct link between the number of officers and the level of crime.

Her approach seemed to hold true as the crime figures continued to fall and the police federation’s predictions of “Christmas for criminals” proved to be unfounded.

At the same time the counter-terrorism budget was protected, with MI5, GCHQ and counter-terrorism policing guaranteed increased funding and resources year-on-year as chief constables faced the dilemma of cutting back on neighbourhood policing teams to balance the books.

The tide turned when the attacks in France in April 2016 prompted a rethink of anti-terrorism policing. David Cameron committed to reversing the decline in armed police officers and made £143m available to recruit 1,500 extra firearms officers by 2021. Contingency plans were also made to put up to 5,000 troops on standby in the event of a terrorist attack.

At the same time May had secured a commitment in autumn 2015 not to go ahead with a further 20% cut in police budgets but instead protect them in cash terms. This was however not before Labour’s then shadow home secretary, Andy Burnham, had actually argued that forces could cope with a further budget cut of up to 10% but that 20% would put community safety at risk.

May wrongfooted Burnham by announcing no cut at all in cash terms and the result is that the decline in police numbers slowed.

That change of course appears to have been accompanied by an official recognition by the government that rather than crime continuing to fall, it is transforming, with new types of crime such as online fraud and harassment demanding different specialist police officers.

Some forces however have continued to feel the pressure as a flawed national funding formula has delivered disproportionate savings to them. Those still facing cuts have shouted the loudest while other chief constables who have started to recruit again have proved less vociferous.

Most prominent of those affected is the Metropolitan police, whose last commissioner, Bernard Hogan-Howe, warned in February against a further round of cuts. On leaving the role, he said: “The bottom line is there will be less cops. There is only so much you can cut and make efficiencies and then you’ve got to have less police and I’m not sure that’s wise in this city.”