Eyes popped among stunned organisers of a north Norfolk charity book sale when they came across two rare first edition volumes of a Jane Austen novel while sorting through donations.

But the discovery lacks a happy ending - both literary and literally - because the third and final volume of her classic Mansfield Park is missing.

Printed in 1814, only 1,250 first edition copies of Mansfield Park were produced and the complete three-volume set could have added more than £16,000 to the Friends of Morston Church's coffers.

'We got very excited about a big contribution to the church repair bill,' said Friends' treasurer Rob Metcalfe, 'until we realised we were one volume short of the set.'

A careful search through the other 20,000 donations to the sale failed to turn up the missing volume three: 'so we would be very keen to hear from anyone who happens to have a spare copy, however unlikely that is!' Mr Metcalfe added.

'We've no idea who gave us the volumes, they were just among all the other books we're given during the course of the year.

'They all get sorted, priced and put in categories and distributed in lofts, cupboards, nooks and crannies all over Morston until they start to re-emerge about now, ready for the sale.'

Past donations to the sale have included a PG Wodehouse first edition which sold for more than £300, but nothing with the potential value of the Jane Austen books has appeared among the filled cardboard boxes before.

Organisers plan to hang on to the volumes for the time being.

The Morston Book Sale, in its seventh year, is a Mecca for book lovers and has raised about £30,000 so far for restoration work at medieval All Saints' Church. The Friends are now saving towards repairs to the church roof, estimated at about £100,000.

? The sale runs from Saturday April 30 to Monday May 2, 10am-5pm, at Morston Barn, Binham Lane, Morston NR25 7AA. Admission and parking are free.