Elected to Parliament in 2005 as MP for Bristol East. McCarthy has served on the Treasury select committee and as a PPS in the Department for Health and the Department for International Development. She was made a junior whip in the June 2009 reshuffle.
- What's her background?
McCarthy attended comprehensive school in Luton before going to Liverpool University. A qualified solicitor, she began a legal career in the late 1980s. More recently, she worked for the Britain in Europe campaign.
- Where does she sit politically?
McCarthy supported Alan Johnson in Labour's deputy leadership contest and is a big admirer of the Prime Minister. She told PRWeek: 'I have real admiration for Gordon Brown.'
- Why is she one to watch?
A prolific blogger and Twitterer, McCarthy is well-known to Labour new media enthusiasts. Her new role will involve co-ordinating Labour's online presence and helping Labour MPs, PPCs and supporters share best practice online.
- Something I might not have known
McCarthy has been a vegan since 1992.