Government officials warned it was 'open season on ministers' last night as Health Secretary Steve Barclay became the latest senior politician to face bullying allegations.

He was accused of 'bad behaviour' towards staff in the Department of Health and Social Care since being appointed last summer.

The Guardian said officials had 'raised concerns', with civil servants complaining informally to Chris Wormald, the department's permanent secretary.

But allies and ex-colleagues of Mr Barclay denied the allegations and suggested civil servants may now feel 'emboldened' to 'go after' ministers they did not like.

It comes after Deputy Prime Minister Dominic Raab quit when a probe found he had upset staff. 

Sources told The Guardian that Mr Barclay – a former Government whip and Brexit Secretary – was 'constantly angry' and had 'blasted' staff, who in turn found him 'quite challenging'.

One source was quoted saying: 'Barclay's style is very macho... he hauls people over the coals and is a bit unpleasant.'

But a source close to Mr Barclay insisted: 'This is all a bit thin. There's been no complaint at any department he's worked in. 

'The allegation is completely untrue.'

A senior civil servant who worked with Mr Barclay in the Cabinet Office said: 'I do not recognise any of these allegations. 

'He was always professional. He set high standards, but he was running a Government department.'

Another said: 'This is open season on ministers.'

Ex-Cabinet minister Jacob Rees-Mogg called Mr Barclay 'effective' and 'tough', adding: 'To translate that into bullying is absurd. 

'Dominic Raab's departure emboldened civil servants to go after a government they do not like.'

The Health Department said it had not received formal complaints about ministers' behaviour.