Pairing is an arrangement between political parties, where two MPs one who would vote Aye and one who would vote No-agree not to vote in a division. The arrangement is generally used in cases of sickness or absence on parliamentary delegations. These arrangements are registered with the whips.
If the tellers from both sides agree, an MP who is within the precincts of the Palace of Westminster but not well enough to vote in person, may be ‘nodded through’. This means their name is added to the list of those voting even though they haven’t gone through the lobby in person.