"Recliner" wrote:

I thought the only time a mortar bomb actually landed inside Heathrow,
it was close to T4, on the south side of the airfield. I left from the
adjacent gate the very next day.

I don't know about the only time, but the IRA definitely parked in what was then
The Excelsior's car park, north of the field and launched mortars out the back
window of the car that landed near the north runway.

I was staying there that night and spent a little time with an interviewer from
The Met going over who I saw in the car park. I still have letters about the
incident The Met and the hotel slipped under my door that evening as a memento.

If you take a look at Google Earth using these coordinates 51°28'54.31" N
0°26'43.66" W you can see the north most taxiways were overbuilt with car parks
and industrial buildings.

It looks like the hotel is now called The Park Inn.