He’s no longer a minister (part of the government), but a backbencher instead. This means:
- he won’t be responsible for a specific part of the UK’s policy / needs any longer.
- he’s not bound by the convention of collective responsibility - i.e. the government is supposed to speak with a single voice on all matters of policy (which is why the media get all excited when one minister contradicts another).
- he’ll get paid less - ministers get an additional salary on top of their MP salary.
- he’ll have to sit a couple of benches further back in the Commons.
He should still do all the normal stuff that any MP does - constituency work, turn up to debates/votes where necessary, ask questions etc.