The Highway Code (Section 217) clearly states that you shouldn't park within 10 metres of a junction.
http://www.highwaycode.gov.uk/22.htm
There appears to be no
specific legislation to back this up but that's not particularly surprising. (There's no law which
specifically states you shouldn't drive on the right-hand-side of the road but doing so would normally fall foul of more general legislation). It seems to come under generic legislation which deals with 'causing an obstruction'
I can certainly confirm that people have received parking tickets for parking too close to a junction. Back in the days when we saw traffic wardens patrolling the streets (rather than the council staff who now do the same job in most areas), the 'Yellow Perils' could often be seen in Clacton-on-Sea, on sunny summer days, measuring the distance of cars from junctions. Many a seaside visitor, who'd parked just
beyond the end of a yellow line, returned to find that they'd still got a ticket.
Chris