The Crofting Commission has begun issuing around 3,500 letters to individuals who missed the deadline to submit their annual notice, a statutory requirement designed to establish whether crofters are resident within 20 miles of their croft and maintaining it properly. Failure to comply is a criminal offence.

Gary Campbell, the commission’s chief executive, said earlier this month that direct action was being taken and warned that failure to return the paperwork “is a serious matter”.

The letters being issued set out the legal consequences of noncompliance and state that cases could be referred to the procurator fiscal if crofters do not respond. The commission said it was unclear why so many had not returned the forms.

Andrew Thin, chair of the Crofting Commission, called the number of non-responses disappointing and urged crofters to comply. “We are writing to 3,500 crofters who have failed to confirm that they are locally resident and using their croft. If you are one of them, please take this seriously,” he said.

Donna Smith, chief executive of the Scottish Crofting Federation, said the figures may reflect confusion around legal duties. “Everywhere I host local meetings with crofters, the biggest issue raised is that of absentee crofters or those who are neglecting their crofts,” she said. “The annual notice is one tool that the commission can use to establish whether crofters are complying with their duties, so we welcome this increased focus on those not returning it.”

She added: “In time this should lead to an increase of activity resolving situations where crofters are in breach of their duties, thereby bringing more crofts back into active use.”

There are approximately 20,000 crofts and 16,000 crofters in Scotland, concentrated largely in the Highlands and Islands. The Crofting Commission estimates that crofting tenure covers more than 750,000 hectares and supports around 33,000 residents.