There have been two cases in the past 25 years when sitting MPs resigned from their respective parties, but in both cases they were members of the opposition.
In 1989 Labour MP Wenzu Mintoff renounced the party whip and represented Alternattiva Demokratika, a new party he helped found after being expelled from the Labour Party.
The other incident happened in 1995 when Labour MP Joe Brincat temporarily fell out with his party and sat in Parliament as an independent MP until the end of the legislature.