Education secretary Gavin Williamson has insisted it was not a mistake to have made major cuts to Ofsted’s budget, as he promoted plans to give the inspectorate an extra £10m.

The new funding - less than ten per cent of the funding cuts which Ofsted have faced in recent years -   was announced as part of a plan to extend inspections of secondaries and large primaries to three days and trial a no notice approach.

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Between 2006 and 2016 more than £100m was cut from Ofsted’s budget. And from 2000  to 2017 the inspectorate’s funding fell in real terms by 52 per cent, according to National Audit Office figures.

Mr Williamson was asked today whether he regretted the fact that Ofsted’s budget had been “cut so significantly in recent years”, by a Conservative government, and whether the new spending announced last night showed the cuts had been a mistake.

Speaking on Radio Four’s today programme he said: “No we are not saying that was a mistake.

“We were dealing with an economic crisis that the last Labour government had created. It was nine years ago but Labour governments always tend to leave you with a big deficit  and more unemployment and we have been dealing with that.”

He said that the £10m was to “strengthen the quality of inspection, the quality of inspectors and making sure some of the larger schools, secondary schools and some of the largest primaries move to a three day inspection”.

Mr Williamson added: “This is just to ensure that they look at a whole range of different things. discipline, PE, sports, enrichment activities that are schools are doing which is an area that a number of different people have raised with us that Ofsted haven’t looked at enough in the past.”

Mr Williamson also criticised other parties’ plans to replace Ofsted.

He said: “The issue that you have, the problem you have with what Labour and the Lib Dems are proposing is that you are going to have to have 152 different inspection regimes by local councils marking their own homework.

“There is going to be no accountability for childrens’ homes or local authorities in terms of what they are doing with their children’s services.”

The Conservatives have also announced that they plan to introduce a trial of no-notice inspections of schools and the party also reaffirmed its commitment to remove the exemption on outstanding schools being routinely reinspected by Ofsted.

A Public Accounts Committee report last year found significant cuts in Ofsted’s budget risked undermining its credibility.

It followed an investigation by the National Audit Office which found that the level of assurance Ofsted could give about school effectiveness had been reduced because of budget cuts.

The inspectorate’s budget has been cut by 52 per cent from 2000 to 2017, according to the NAO report.

It also said that between 2006 and 2016 the inspectorates’s budget  had fallen from £280 million to £167 million, a drop of 40 per cent in real terms.