Warren Hastings, the Governor of India (in pre-Mutiny/pre-Viceroy days) was impeached even before the United States had a President to impeach...
An individual can be impeached by Parliament for 'High crimes and misdemeanours', with the Commons calling for impeachment and the trial taking place before the Lords. However, the parliamentary website says:
However since 1805 parliamentary procedure has changed. The Cabinet is responsible for the actions of Ministers and Ministers are accountable to Parliament. Their work is scrutinised and they are questioned regularly by Parliament. There is therefore no need for impeachment.
- although I confess that I can't quite see the logic behind this: being accountable to parliament via being questionned isn't the same thing as being up before their Lordships for high crimes and misdemeanours...