As Pakistani Passport holder and a Schengen visa holder do i need aTransit Visa for Manchester [duplicate]

If you are not leaving the airport, or not switching airports, and your transit is less than 24 hours, then you do not need a transit visa; on the basis of your Schengen D visa.

See the requirements:

Exemptions You don’t need a visa if you have one of the following:

• a visa for Canada, New Zealand, Australia or the USA (this can be used for travel to any country)
• a residence permit issued by Australia or New Zealand
• a common format residence permit issued by an European Economic Area (EEA) country or Switzerland
• a resident permit issued by Canada after 28 June 2002
• a uniform format category D visa for entry into a country in the European Economic Area (EEA) or Switzerland
• an Irish biometric visa (marked ‘BC’ or ‘BC BIVS’ in the ‘Remarks’ section)
• a Schengen Approved Destination Scheme (ADS) group tourism visa where the holder is travelling to the Schengen country that issued the visa a flight ticket from the Schengen area, if you can prove that you entered the Schengen area in the previous 30 days on the basis of a valid Schengen ADS visa
• a valid USA I-551 Temporary Immigrant visa issued by the USA (a wet-ink stamp version will not be accepted)
• a valid USA permanent residence card issued by the USA on or after 21 April 1998
• an expired USA I-551 Permanent Residence card issued by the USA on or after 21 April 1998, with a valid I-797 letter authorising extension a valid standalone US Immigration Form 155A/155B issued by the USA (attached to a sealed brown envelope)

All visas and residence permits must be valid.