Other obvious barriers are regulatory - volunteers might need to agree to criminal record checks and there might need to be some form of inspection regime.

BBC: Eight radical solutions to the childcare issue

It is acceptable to take a punt on a promising youngster on a tour - as is the case with Adil Rashid - but not on a 34-year-old whose form, on last inspection, had deserted him.

BBC: Jonathan Agnew column

Genetic markers for the bacterium were sent to America and the Animal and Plant Health Inspection Service confirmed in July that the same form of Candidatus had been found in potatoes from two fields in Texas that were exhibiting zebra-chip symptoms.

ECONOMIST: Plant disease