The slashing of Entrepreneur’s Relief in the Budget will be a major factor in the increase but not the only one.

Receipts from CGT in 2013/14 were £3.9bn but Treasury forecasts predict CGT receipts will soar to £15.7bn by 2023/24 and £17bn a year later.

Sean McCann, a Chartered Financial Planner at NFU, said CGT already provides more cash to the Treasury than tobacco duty and will soon outstrip alcohol duties.

In 2013/14 Alcohol duty brought in £10.5bn in revenue for the government compared to £3.9bn for CGT. By 2023/24 Alcohol duty is forecast to bring in £12.8bn but CGT will ring in £14.3bn.

CGT receipts

Source: NFU, Treasury

Mr McCann said more people were being caught out by CGT.

He said: “Capital gains tax catches many unaware and those selling or giving away property or investments often end up paying more than they need to.

“While much of the projected increase will be down to the slashing of Entrepreneurs’ Relief, there are other contributing factors.

“The changes to the tax treatment of mortgage interest on buy-to-let properties has led many to sell up triggering capital gains tax bills.       

“Similarly, many long-term investors in the stock market have benefited from large gains, but the recent downturn may have encouraged them to sell exposing gains to tax.”

He said steps such as sharing ownership of assets between spouses or civil partners and giving away business assets or making gifts to trusts may would help defer Capital Gains Tax.

He said good financial advice was key before selling assets or making gifts.