28/09/2015 12:39 BST | Updated 28/09/2016 06:12 BST

England's Heritage: A Taxing Opportunity

Open House London, the capital's greatest architectural festival, has just completed a successful weekend. Hundreds of fine London buildings of all types and periods, and that are not normally open to the public, were freely available to all..

This is therefore a good time to revisit the tax reliefs available when national heritage assets are made available for public access.

Where the conditions are met and exemption is granted by HM Revenue & Customs, the available relief is generous - assets can be exempt from either a capital gains or inheritance tax charge on a transfer of the asset, either as a gift or on death. Heritage assets can include buildings or estates with outstanding historical or architectural interest, land of outstanding natural beauty or scientific interest and objects of scientific, historic or artistic interest. HMRC publish a list of assets where exemption has been granted and details of how access may be obtained.

The level of access varies from property to property depending on factors such as features of interest, size, location, contents and other individual circumstances. As a general guide, "reasonable public access" is access on at least one day a week plus public holidays during the spring and summer months amounting to 28 days each year (25 days in Scotland, Wales and Northern Ireland). Fewer days can be agreed in special circumstances.

The exemption is only conditional - where the conditions are no longer met, or the property sold, exemption may be withdrawn and tax will become payable.

As well as the tax reliefs, other factors will need to be considered - opening up a property to the public for the first time may constitute a change of use requiring the consent of the local planning authority and adequate insurance will need to be in place.

Despite the complexities, for many families who may hold assets of national interest, the relief can be a valuable opportunity to manage tax liabilities through the generations and still "keep it in the family".