Karachi is 5 hours ahead of London during GMT, and 4 hours ahead during BST. When it's 12:00 PM in London (winter), it's 5:00 PM in Karachi. Pakistan does not observe DST.
Pakistan uses PKT (UTC+5) year-round while the UK switches between GMT (winter) and BST (summer). The difference is 5 hours in winter and 4 hours in summer.
Good overlap! 9:00 AM - 2:00 PM London (winter) corresponds to 2:00 PM - 7:00 PM Karachi. Morning London catches Karachi's afternoon.
Karachi is Pakistan's largest city and economic hub. The UK has a significant Pakistani diaspora, making this a busy route with PIA and British Airways flights.