score:7
No, there is no need to pass through immigration control in this circumstance.
Simply follow the purple signs to the new terminal. The inter-terminal bus system is before immigration control.
See also: http://www.heathrowairport.com/heathrow-airport-guide/flight-connections/connection-guides.
If you are flying BA then you are in Terminal 5 for both flights, and there will be no need to use the buses.
Upvote:-1
You may need cross the border control. As per https://www.gov.uk/check-uk-visa
Below is the excerpt
Will you pass through UK border control?
You always pass through border control if you:
You must also pass through border control if both:
Check with your airline if youβre not sure if youβll pass through border control.