There are 17 parties represented in the UK House of Commons right now, based on live parliamentary data.

A few helpful caveats:

  • The UK Parliament includes the House of Commons and the House of Lords, but “parties in parliament” usually means the Commons.
  • The exact number can change after by-elections, defections, or new party gains.
  • The Commons has 650 seats in total, and the largest party at the moment is Labour.

If you want, I can also list the main parties and how many seats each has.