Hi' I was at LHR today, when I noticed there was an A319 BA at the front, about 50 metres away from takeing off, which had stopped. The traffic behind had to get on the runway and take-off without useing all the runway(about 1/6th less of the full length) Every aircraft had to do this for at least 30-40mins (aircraft including 744's, A343's & A346's, 773 etc). After about 40 mins, I saw a yellow jeep escorting a tug to the a319, and picked it up and had to taxi down 1/4 of the runway. Traffic obvoiusly had to stop because of this, and the take-off queue was extremely long for a long while afterwards.
I don't know whether the a/c had engine trouble, or maybe passenger trouble, but I bet the a346/b773 pilots didn't enjoy only have 5/6ths of the runway (9R)
Does anyone have any other info about this?