Letterman apologises for Palin joke

David Letterman has apologised for his "sexually perverted" comments about one of Sarah Palin's daughters, amid calls from conservative groups for his resignation and boycotts of his show by viewers and advertisers. A group of Palin supporters are even planning a rally tonight outside the show's studio at the Ed Sullivan theatre in New York's Times Square, despite Palin announcing today that she accepts Letterman's apology.

The 'Fire David Letterman' group, which includes Republican New York State Assemblyman Brian Kolb, are comparing Letterman's case to that of CBS radio host Don Imus, who was fired in 2007 for offensive comments about a black women's basketball team. On their website the group calls for Letterman to "be accountable for his disgraceful statements". A Facebook page set up for the rally has already attracted 1,369 comments and several hundred protestors could attend tonight.

The firestorm started when the TV talk show host joked during last Monday's taping of Late Night with David Letterman that New York Yankees slugger Alex Rodriguez had "knocked up" the Alaska Governor's daughter during a family trip to a baseball game.

Letterman tried to clear the air at the time, saying that his intended target was Palin's oldest daughter, 18-year-old Bristol - a high-profile campaigner for teen abstinence despite having had a son, Tripp, out of wedlock last December. Letterman did not realise, he said, that 14-year-old Willow Palin was the only one of Palin's children to attend the game. Despite the explanation, an angry Palin maintained that the "sexually perverted comments" made by the 62-year-old presenter were "disgusting".

Last night Letterman admitted his joke was "beyond flawed". He added: "My intent was completely meaningless compared to the [audience's] perception".

Letterman also said he was sorry to Palin and both her daughters. "I would like to apologise, especially to the two daughters involved, Bristol and Willow, and also to the Governor and her family and everybody else who was outraged by the joke. I'm sorry about it and I'll try to do better in the future. Thank you very much."

Sarah Palin issued a statement today accepting Letterman's apology.