When an aircraft has a missed approach at LHR does it have to go to the back of the queue at say LAM or does it get vectored in as priority?
As Roffa says, the missed approach will be re-sequenced into the traffic flow, not as "a priority", but simply as another arrival (if the go-around was a heavy, it may be planned to group it with another heavy or behind a 757). Realistically, this will mean that traffic being brought off the stacks will have an extra couple of track miles to fly to accommodate the sequence, as a gap will have to be made. Heathrow's sequencing is all about track mileage and the number of aircraft off the stacks vs where the arrivals will be turning to final.
They will be afforded a little bit more room ahead on final to ensure it doesn't happen again (
) .