Most of us would not think twice about driving down Hoop Lane, the road linking Golders Green to Hampstead Garden Suburb.

But for a select group, it has been a religious hazard best avoided. Conscientious Cohanim have given it a wide berth because of the dangers of ritual impurity from the adjacent Jewish cemetery.

Cohanim are forbidden contact with a dead body by Jewish law and are allowed to go to the graveside only at the interment of close relatives such as a parent.

Under halachah, if an area containing graves is covered by a tree, it becomes a source of ritual contamination for priests. The problem at Hoop Lane is the trees whose branches overhang both the cemetery and the road.

But now the Va'ad Mishmeres Hakohanim, the Committee for the Protection of Priests, has found a simple solution to make Hoop Lane passable - pruning the trees.

As the Va'ad's Eli Katz explained: "The trees have to be pruned either over the cemetery or the road. It didn't require a lot of pruning. It is now safe for a Cohen to travel by car in both directions or walk on the opposite side of the road from the cemetery."

A number of rabbis oversaw the work, among them former London Beth Din head Dayan Chanoch Ehrentreu and the senior rabbi of the S and P Sephardi Community, Rabbi Joseph Dweck, both of whom are Cohanim.

The laws regarding priestly impurity are strict and Mr Katz pointed out that it was a transgression for an ordinary Jew to take a Cohen into an area he is forbidden to enter.

In old cities like London, the multiplicity of graveyards can make life tricky for priests.

For example, the park opposite Lord's Cricket Ground in St John's Wood was a church burial ground and the branches of the trees stretch over the road.

While this was not as problematic a scenario as a Jewish cemetery, Mr Katz said it was still "appropriate [for Cohanim] to refrain" from driving into town from Swiss Cottage using Wellington Road.