best way is to obtain Turkey UK & Schengen visa, land in Turkey rent a car and drive across europe & uk and return by air. Hertz & Avis have cross border rental vehicle arrangements.
driving from pakistan to uk under present situation is impossible. you may have to place a bank guarantee of 100% vehicle invoice value with customs for vehicle return to country. arrange international insurance and obtain carnet. etc etc.
if you search in travel section there are plenty of pages and several topics covering the subject. Valuable genuine procedures and suggestions are mentioned.