Slough MP Fiona McTaggart has given a cheque for more than £14,000 to Comic Relief after an impromptu Twitter drive.
Just after 1pm yesterday, the Labour member Tweeted: "I will give £1.00 to Comic relief for every retweet of this message before 9pm."
The tweet then got 14,268 retweets, with a further 4,802 after the deadline.
Although she had always planned to write a cheque for Comic Relief, the Labour MP said she had the sum of £10,000 in mind, and admitted she was "a bit" worried as the number of retweets steadily increased.
Ms MacTaggart said she believes generosity "should hurt a bit", and expressed her shock at the difference in charitable giving between rich and poor people.
"I think generosity should hurt a bit and one of the figures that has always shocked me is that poorer people give between 4% and 5% of their income to charity, and richer people give around 2% of their income to charity."
The MP received a number of negative tweets suggesting that she would claim the donation back on her expenses. She said: "I was surprised by that, and depressed by it. I had always planned to write a big cheque for Comic Relief. Doing it that way wasn't a carefully planned campaign. I think if it had been it would have cost me a lot more, because people would have been ready to start retweeting as it were.
And to the suggestion that she could have given the money without drawing attention to it, she said that many of those who retweeted were spurred into giving themselves.
She said: "What I thought about was, 'If I do it this way, a lot of people will get Red Nose on their timeline who aren't watching the television but who are looking at other media and maybe they'll give.'
"And actually, lots of them did."
"When I was a teacher, before I was an MP, I taught for the whole day dressed up as a chicken, and got sponsored for Red Nose Day."
Ms Mactaggart said the cheque has already been handed over to Comic Relief.
This year's Red Nose Day has raised £75,107,851 so far.