New rules aimed at protecting UK museums and galleries from losing valuable items to overseas buyers will be introduced from January 1, the Government has said.

Under the current system, a pause in the export of national treasures overseas can be ordered by the Culture Minister to give UK museums and buyers the chance to raise funds to keep them in the country.

If a UK institution puts in a matching offer on an item subject to an export deferral, and the owner has agreed to sell, it is down to the seller to honour that commitment.

Although a rare occurrence, in the last five years eight items have been lost to UK collections when a seller refused to honour the “gentleman’s agreement”, resulting in months of vital fundraising work by national institutions going to waste.

The Department for Digital, Culture, Media and Sport (DCMS) said that from next year legally binding offers will see an end to the gentleman’s agreement.

In 2017, the National Gallery raised £30 million to acquire a work which was subsequently pulled from sale by the owner.

The introduction of legally binding offers, which marks the first major change in the export deferral system in over 65 years, will mean that this can no longer happen, the Government has said.

Culture Minister Caroline Dinenage said the new rules will mean more works can be saved and used for “educating and inspiring generations to come”.

She said: “Our museums and galleries are full of treasures that tell us about who we are and where we came from.

“The export bar system exists so that we can offer public institutions the opportunity to acquire new items of national importance.

“It is right that this crackdown will make it easier for us to save items and avoid wasted fundraising efforts by our museums.”

National Gallery director Dr Gabriele Finaldi added: “I welcome the new rules that remove the ambiguities that have led to major works of art being lost to the nation. The clarity will be beneficial to museums and vendors alike.”

Funds from the DCMS have also been made available for the development of a new digital system for export licences, which will be overseen by Arts Council England.

The new system, which is expected to be running by autumn 2021, will allow sellers to apply for their export licence online, aimed at saving time, effort and expense.

Items that have been saved through the current system include the sledge and flag from Ernest Shackleton’s Nimrod Antarctic Expedition of 1907-9, which has been acquired by the National Maritime Museum and the Scott Polar Research Institute, and Salvador Dali’s Lobster Telephone and Mae West Lips Sofa, which were acquired by the National Galleries of Scotland and the Victoria and Albert Museum.

Lawrence of Arabia’s steel and silver dagger, which found a home at the National Army Museum, and the notebooks of Charles Lyell, Darwin’s mentor, that were acquired by the University of Edinburgh, were also kept in the UK.

In the 10-year period ending in 2018-19, 39% of items at risk of leaving the UK – worth a total of £103.3 million – were retained by UK institutions, according to DCMS.