The Attorney General has rejected calls from Conservative MPs to investigate the RSPCA's prosecutions.

And the Charity Commission and the RSPCA have both denied leaking a letter to the Telegraph newspaper about the charity's prosecutions.

The denials came just hours before a Westminster Hall debate on the RSPCA today which saw the charity accused of using prosecutions to drive a political ideology and in turn defended as an upholder of the law.

Conservative MP Simon Hart, who led the debate, accused the RSPCA of being a prosecutor which did “politics in a big way”.

He also said there was a “gulf between the very good activity of inspectors on the ground whose principal concern is animal welfare and the leadership whose principal concern seems to be animal rights”.

In the debate, Hart referred to a leaked letter reported in the Telegraph today from Charity Commission chief executive Sam Younger to Gavin Grant, chief executive of the RSPCA.  Hart said the Charity Commission "rebuked" the RSPCA in the letter.

According to The Telegraph, Younger's letter said the RSPCA should review its prosecution policies “given the amount of adverse publicity and the allegations of political bias that the charity had attracted as a result of the case”.

The Charity Commission refused to comment on the letter and its contents and told civilsociety.co.uk this morning that it did not send it to the Telegraph. An RSPCA spokeswoman said: “You can be pretty safely assured that the RSPCA did not send the Telegraph the letter.”

Parliamentary debate

The parliamentary debate today centred on the RSPCA’s prosecutions. It follows a political row between a group of cross-party MPs who have called on the Charity Commission to investigate the RSPCA’s prosecution of the Heythrop Hunt, the first successful prosecution of a hunt brought in the UK. The Charity Commission has said there is no regulatory concern and it will not investigate the charity.

During the debate a number of Conservative MPs said the RSPCA had turned from a body concerned with animal welfare to a body following a political ideology of animal rights. MPs also warned that there was a public perception that its prosecution of hunts were political.

Tory MP Glyn Davies warned that the RSPCA would lose support for becoming too concerned with animal rights and not animal welfare.

Opposition MPs defend RSPCA

However a number of Labour MPs, and Green MP Caroline Lucas, defended the RSPCA.

Labour MP Emily Thornberry accused Conservative MPs of being disappointed that the government would not change laws on hunting, so they’d turned on the RSPCA instead.

Lucas also called the debate a “smokescreen” asserting that the RSPCA was within its rights to uphold the law.

Another Labour MP also said it was a smokescreen for the RSPCA having the temerity to prosecute a hunt in David Cameron’s constituency.

Earlier this month, Hart said there was a "political edge" to RSPCA’s prosecution of the hunt, saying it was odd that they targeted Cameron’s constituency.

Ending the debate, the Attorney General Dominic Grieve QC rejected calls to investigate the RSPCA’s prosecutions, saying to do so would be "too difficult".