The Charity Commission has written to the trustees of a school following allegations that its headteacher misused funds including increasing his own salary by 381 per cent over 11 years.

The BBC has reported that David Craggs, headteacher at Gad’s Hill School in Kent, which is registered with the Charity Commission, did not contest reports that raised concerns over misusing funds.

It also reports that since Craggs started the role in 2000, his income increased from £35,130 by 381 per cent to £168,985 in 11 years.

However, the school’s most recent accounts suggest his income went down to £122,995 in 2013.

Kirsty Hillocks, acting chair of governors at Gad's Hill School, said allegations were first raised in March 2012 by John Melville, who resigned as chairman of the board of governors in April over the claims. An investigation took place at Melville's request but the headmaster was cleared of any wrongdoing.

“The governing body initiated an investigation which concluded that the headmaster of Gad's Hill School had not breached any school policy or procedure and therefore would not be subjected to any disciplinary process,” she said.

She said that the governing body referred the matter to the Charity Commission at the time, and it concluded that the “school may need to review some of its internal procedures but that it had acted appropriately and saw no need for any further action”.

Hillocks stated that Melville was fully aware of the investigation and its outcomes at the time.

But the Commission said it was never made aware of the alleged misuse of funds and so has decided to reopen the case in light of the BBC report.

A spokeswoman from the Charity Commission said that the concerns highlighted by the BBC are “serious” and that the regulator has written to the trustees to get more information.

However she added that the Charity Commission is not formally investigating the charity at this time.

She said: "The issues brought to our attention by the BBC in connection with Gad’s Hill School appear to require further regulatory assessment and we have written to the trustees asking for their comments.

“While the trustees had informed us of the financial review they undertook, we did not receive any notification of alleged misappropriation of funds. Any such concerns are serious, and it is the trustees’ responsibility to report these to us in a serious incident report.”

She said that the Commission is awaiting the trustees’ response and will consider what action, if any, to take on its receipt.