The sale and export of almost all ivory could be banned in the UK under new plans set out by the government.

The surprise move, which had been removed from the Conservative Party's 2017 election manifesto, comes following pressure from activists who have long sought to put an end to the UK's role as the world's biggest exporter of legal ivory carvings and antiques.

This includes well-known campaigners such as Prince William, Ricky Gervais, Stephen Hawking and former Tory leader William Hague.

About 20,000 elephants are killed every year to feed the ivory trade, leaving conservationists to fear some species could go extinct.

Environment Secretary Michael Gove, who announced a consultation on the proposed ban on Friday (6 October), said: "The decline in the elephant population fuelled by poaching for ivory shames our generation. The need for radical and robust action to protect one of the world's most iconic and treasured species is beyond dispute. These plans will put the UK front and centre of global efforts to end the insidious trade in ivory."

Current rules ban raw ivory but allow the sale of "carved" or antique items made before 1947.

It has allowed the UK to become the world leader in legal ivory exports, with more than 36,000 items sent abroad between 2010 and 2015 – more than three times that of the next biggest exporter, the US.

Conservationists say the sales, often to Asian countries such as Hong Kong and China, stimulate demand for the product and in turn lead to increased elephant poaching.

The new ban ends the trade in ivory of all ages, while still providing some exemptions for musical instruments, items of cultural importance, items with only a small proportion of ivory and sales between museums.

The new proposals were welcomed by the John Stephenson, head of campaign group Stop Ivory.

"The unprecedented crisis we face – with Africa's natural heritage being destroyed and communities put at risk due to poaching by illegal armed gangs – will only stop when people stop buying ivory," he said.

"Along with our partners, we congratulate the government on this important step and look forward to working with it to ensure the ban is implemented robustly and without delay."

Previous attempts by the Conservatives to further restrict the sale of ivory have failed, including last year by Gove's predecessor, Andrea Leadsom, who announced a ban on sales of post-1947 ivory which was never consulted upon. It was then quietly dropped by Theresa May from the 2017 Conservative Party election manifesto.

Gove's proposals will see a 12-week consultation start immediately, closing on 29 December. It will likely give the government better standing when the UK hosts a major illegal wildlife conference next year.

Tanya Steele, WWF's CEO, said governments across the world needed to work together to ensure an end to the ivory trade and elephant poaching.

"This illegal trade involving organised criminals is a global problem requiring global solutions: to end it anywhere means ending it everywhere," she said.

"This is about a lot more than banning ivory sales in one country. It means working with global leaders and communities around the world, particularly in China and south-east Asia, to implement bans and stop the illegal trade."

Not everyone is happy with the proposals, however. Noelle McElhatton, from the Antiques Trade Gazette, said those involved in the trade abhor poaching but don't believe the government's proposals will "save a single living elephant".

"We feel strongly that an outright ban would be an over-reaction and would be very detrimental to the honest and legitimate trade of pre-1947 ivory," she told the BBC.