Gay playwright Alan Bennett has blasted Tory MPs who excuse the actions of the late Baroness Margaret Thatcher, calling her a “seriously flawed human being” whose lack of humour shut her off from humanity.

In diary extracts published in the latest issue of the London Books, the 78-year-old author wrote: “Mrs Thatcher was a mirthless bully and should have been buried, as once upon a time monarchs used to be, in the depths of the night.

On April 17, the day of the former Prime Minister’s funeral at St Paul’s Cathedral, Mr Bennett wrote: “Shots of the Cabinet and the ex-cabinet at Lady Thatcher’s funeral in St Paul’s just emphasise how consistently cowardly most of them were, the only time they dared to stand up to her was when eventually they kicked her out.

“What also galls is the notion that Tory MPs throw in almost as an afterthought, namely that her lack of a sense of humor was just a minor failing.

“In fact to have no sense of humor is to be a seriously flawed human being. It’s not a minor shortcoming; it shuts you off from humanity.”

In response to Mr Bennett’s comments, former senior cabinet minister Lord Tebbit said: “Whether he is a good playwright or not, he’s obviously pig-ignorant about British history and Margaret Thatcher.”

Mr Bennett, who is in a civil partnership, previously admitted that he did not understand “what all the fuss was about over gay marriage.”

In April, actor Sir Ian McKellen said Margaret Thatcher “misjudged the future” with her support for Section 28.