Voters overwhelmingly back increasing the tax paid on profits from selling shares, second homes and valuable possessions, research reveals today.
Three in five Britons want capital gains tax raised to bring it in line with income tax, a poll showed.
Experts believe it could pump £14billion into Treasury coffers.
CGT is paid on profit from things like flogging artwork and holiday boltholes.
The first £12,300 is tax-free and analysts say the tax rate paid is between 10% and 28%.
In comparison, workers earning ordinary wages are taxed at between 20% and 45%.
Critics claim that relatively low CGT rates disproportionately benefit the wealthy because they are more likely to own shares, second homes and expensive goods.
They also believe it is unearned wealth because the person who trousers the profit often carries out little or no work to reap the reward, simply pocketing cash from trading property, stocks or possessions they are given or inherit.
Some 61% of people quizzed in a Savanta ComRes survey for campaign group 38 Degrees wanted the tax increased at next month’s Budget.
More than 90,000 people have signed a petition calling on Chancellor Rishi Sunak to raise CGT and bring it in line with income tax.
The drive comes after a consultation by the Office of Tax Simplification published last autumn highlighted a number of areas where CGT is “counter-intuitive” and “creates odd incentives”.
Ashley Bertie, head of campaigns at 38 Degrees, said: “The public has spoken – it’s clear that the Chancellor must increase capital gains tax in March.
“The public supports it, his own experts at the Office for Tax Simplification recommend it, and it could raise a massive £14bn for the Treasury.
“The disparity between CGT and income tax would be unfair at the best of times, but it hits particularly hard when the Government is facing such a long road to recovery from the coronavirus pandemic.”
Tax Justice UK executive director Robert Palmer said: “When the Chancellor raises taxes it is crucial those with the broadest shoulders take the strain; this poll shows the public agree.
“The Government’s own figures show that equalising capital gains with income tax will raise £14bn a year to help build great public services and a healthy economy after Covid.
“Given today’s polling, this move is a political no brainer.”