The BBC has said that Apple owners will be able to download programmes using its iPlayer service by the end of the year.

Writing on a blog, Mark Thompson, the corporation's director general, said the availability of the iPlayer for Macs was "evidence of the hard work that the BBC is committing to supporting other platforms."

Mr Thomson was responding to criticism from MPs that the BBC was effectively handing "illegal state aid" to Microsoft by releasing a version of the iPlayer that was only compatiable with Windows computers.

In his blog post, Mr Thomson said that the decision to launch a Windows-only version had been about "making the service available in the shortest time frame to the greatest amount of users."

He added: "Were we to choose to not develop any systems or services until they could be received by every single individual licence-fee payer, our capacity for development and innovation - in the interest of serving those who fund our services - would be severely limited."

About 90 per cent of computers used the Windows operating system, he said.

Last month John Pugh, the Liberal Democrat MP who is also a member of the House of Commons Public Accounts Committee, wrote a letter to Mr Thomson in which he accused the corporation of illegally supporting Microsoft.

"What might be a pragmatic choice for a privately funded company becomes deeply problematic for a public corporation," Mr Pugh wrote.

The iPlayer, which allows viewers to watch BBC programmes via the internet, comes in two versions: one which streams shows over the web, and can be accessed on any computer, and another which lets people download shows, and so far only works on PC.

Mr Thomson said that since December, Apple owners had been able to stream programs to their Mac, and that a download service was now available using the Firefox web browser.

"I recognise that to many people's minds making this service available to only a proportion of users was not the correct decision, and I accept that for some there is nothing I could say to justify this choice," he wrote.

"I hope, however, that those people might at least appreciate why the BBC believed that making the service available in the shortest time frame to the greatest amount of users was the most effective and responsible way of serving our licence-fee payers."

More than 3.5 million shows have been streamed or downloaded using the iPlayer since its official launch on Christmas Day.

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