His wife Sharon runs the diversified side of the farm business which includes a wedding venue in converted traditional farm buildings.

Rydal Hall Farm is part of the 12,500-acre Rydal Hall Estate which dates back to the 15th century and is still owned by the Le Fleming family.

Illegal and inconsiderate parking is a common problem throughout the Lake District and other beauty spots across Britain.

Roads and entrances to properties and land are routinely blocked, hampering emergency vehicles and making pavements impassable.

Cumbria Police said they were investigating the incident.

A spokesman said: ‘Police were made aware at 10pm on the 25th May of reports of cars having been sprayed with suspected cow slurry at a location near to Rydal.

‘Our Neighbourhood Policing Teams are carrying out further inquiries to determine the full circumstances.’

Cumbria Police urge visitors to the national park only to leave their vehicles in an ‘appropriate place’ so as not to block any drivers, especially emergency service vehicles.

But during the recent hot weather more than 50 fixed penalty notices have been issued by police across the Lake District.