The National Trust will sell off all its shares in fossil fuel companies and use the funds to invest in green start-ups, it has announced.

The Trust, which is the largest conservation charity in Europe, has a stock portfolio worth £1 billion, around 4% of which is invested in fossil fuel companies.

It said it will take three years to complete the sale in order to ensure maximum value, but added that most shares would be sold within 12 months.

The National Trust had been willing to invest in businesses that generate less than 10% of their revenues from thermal coal or oil from tar sands. It follows a very similar move made by the Church of England in 2015, which decided to scrap investments in companies that did not meet the standards set out in the Paris climate agreement by 2023.

Speaking to the BBC, Peter Vermeulen, chief financial officer for the National Trust, said: "Over the years, we've gradually evolved our investment strategy to reduce our carbon footprint.

"As a conservation charity [we] believe that after decades' worth of lobbying, not enough has been done by the oil and gas companies, and for that reason we're looking to withdraw our investment and invest in companies that are looking to deliver environmental benefits as well as financial returns."

Mr Vermeulen did acknowledge efforts made by big oil and gas firms such as BP and Shell to increase their investment in renewable energies but called on them to do more.

He said their investments were "not insignificant" and "too small as a proportion of their total capital investment".