A more thorough explanation:

A teller in Parliament is a member of the British House of Commons who is appointed by the Speaker to count votes. There are two tellers from the government and two from the opposition.

During a vote in the House of Commons, the Speaker will appoint four tellers to count the votes. Two tellers will be from the government and two from the opposition. They will stand at the entrance to the voting lobby and count the number of members who enter.

For example, if there are 300 members in the House of Commons and 200 vote in favor of a bill, the tellers will count the number of members who enter the voting lobby and ensure that the number matches the number of votes cast.

The role of the teller is important in ensuring that the voting process is fair and accurate.