According to the BBC news (in Brexit: PM in new battle after Commons vote defeat published 30 minutes ago) the Conservative Party “expelled” 21 MPs for voting against instruction:
Meanwhile, No 10's decision to expel 21 Tory MPs for defying the party whip on Tuesday continues to causes recriminations in the party.
What does this this mean for those 21 MPs? Do they still have their seats with ability to vote but without party affiliation, or have they also lost their seats?
In Australia (where I'm from) situations like this happen sometimes—an MP votes against their party in spite of instructions—and sometimes that means the MP simply loses their party affiliation and becomes an independent. I'm not sure if that's the same or different here in the UK.