This is hardly surprising given that allotments are measured in rods and poles -- a measurement that dates to Anglo-Saxon times.

The accepted size of an allotment is 10 poles -- the equivalent of 250 square metres, about the size of doubles tenis court -- but many of today's generation of gardeners prefer a small plot of 5 or 2.5 poles.

Barnet's allotment holders gave a cheer when the cabinet office minister Michael Gove announced that tending an allotment counts as a form of permitted exercise so long as social distancing is maintained.

"I think it is perfectly sensible for people to go to an allotment," he told BBC Breakfast News once the lockdown was announced.

"It is in the very nature of an allotment that there is a safe distance between people on individual allotments."

But he made clear the government's ban on gatherings of more than two people must also be observed on allotments.

Guidance has been issued by the National Allotments Society.

Plot holders who are over 70 with underlying health conditions and who are in self-isolation and who are being shielded, have been reminded that they "must not visit" sites until they are out of self-isolation.

Byng Road Allotments Group, part of the Barnet Allotment Federation, has backed up the national advice with a strict protocol.

"We all realise how lucky we are right now to have a plot and somewhere to escape to. Please let us all keep it as safe as we can.

"The points of contact are the water butts and the gates. Please follow the guidance and do not wash your hands at the water butt.

"Use of wipes/sanitiser/gloves at the gate and at the water taps is also necessary."

Plot holders at Byng Road allotments -- where there is a long waiting list -- recognise they are in a privileged position in being able to exercise safely out of doors with coutryside all around them.

"Are so fortunate in having plots that look out across the Green Belt. We can enjoy the fresh air and get on with our cultivation, a real bonus when so many people are confined to their homes with few options for safe exercise."