Luke Bozier, a former senior Labour adviser and co-author of the Labour Business report, defected to the Conservatives on Monday. Bozier is the newest addition to a long line of people who have defected from their party to join the ranks of their former enemies.
Some MPs have come under fire for switching allegiances, but have subsequently gone on to do very well in their new parties. One or two have even made it into the Cabinet.
Here are the top five political defectors in British politics in recent years.