Birmingham City Council ‘failed to support’ a number of schools in protecting children from extremism, Ofsted chief Sir Michael Wilshaw has said.

Delivering the findings of recent inspections, Wilshaw warned a ‘culture of fear and intimidation’ had developed in a number of schools under investigation over allegations of a takeover plan by Islamic extremists.

He warned governors had ‘exerted inappropriate influence on policy and day-to-day running of several schools’ in the city, with some ‘trying to impose and promote a narrow faith-based ideology’ in non-faith schools.

Concerns were initially raised when a Trojan Horse letter alleged Islamic extremists were attempting to take over the governing bodies of local schools. Of the 21 schools inspected following the reports, five have now been placed in special measures and a sixth rated ‘inadequate’.

In a letter to education secretary Michael Gove, Wilshaw said Birmingham City Council had ‘not dealt adequately’ with complaints from head teachers about the conduct of governors.

‘A number of school leaders said that they had not been supported by the local authority in their efforts to keep pupils safe from the potential risks of radicalisation and extremism,’ Wilshaw said.

‘Some head teachers who spoke to me had very little confidence that the local authority would respond to their concerns about governors. Some raised questions about the close links that exist between local authority officials and key governors in the city.

‘In several of the inspections of maintained schools, inspectors noted weaknesses in the local authority’s arrangements for the general oversight of schools,’ he added.

A response published on Birmingham City Council’s website said: ‘First and foremost the responsibility for good governance rests with schools themselves – and individual governors should be looking to themselves when it comes to accountability for the issues raised by Ofsted.

‘However, we recognise that in addition to this the council, the Department for Education and Ofsted have an obligation to ensure a robust assurance system exists to support and challenge – including intervening in – schools to ensure they fulfil their responsibilities. We will consider very seriously Ofsted’s comments that a number of school leaders had not been supported by the local authority in their efforts to keep pupils safe.’

Yesterday, prime minister David Cameron called for a ‘robust response’ to reports of Islamic extremism. However, a statement from Park View Educational Trust - which said it ‘wholeheartedly’ disputed the ‘inadequate’ rating awarded to Park View, Golden Hillock and Nansen schools.