A total ban on ivory sales in the UK could still be introduced by the British government, foreign secretary Boris Johnson has said, signalling a possible U-turn that has been welcomed by conservationists.

In their 2015 manifesto the Conservatives promised to “press for a total ban on ivory sales”. But the pledge was quietly taken out of this year’s Tory manifesto, sparking anger among conservation organisations, which say that by allowing the trade to continue, the UK is fuelling elephant poaching.

Now Johnson seems to have returned to the Conservative’s previous position, saying the government still “intends to pursue” an all-out ban.

When questioned about the government’s stance on the ivory trade in the House of Commons on 11 July, he said: “We have a commitment in this government to an all-out ban on the sale of ivory in this country and that is what we intend to pursue.”

Animal rights campaigners welcomed his declaration. Heather Sohl, chief adviser on wildlife at WWF-UK, called it a “promise that many have been waiting a long time for. With an elephant being poached on average every 25 minutes, it’s clear that urgent action is needed.”

Charlie Mayhew, chief executive of Tusk, said the UK-based wildlife NGO was “naturally encouraged” to hear Johnson’s statements. “We believe that the government will follow through with new legislation to curb the ivory trade in the UK.”

He said it would be “too shaming” if the UK does not close down its domestic trade, considering it will host the next major international conference on the illegal wildlife trade in 2018. “It is imperative that we demonstrate to the world that the UK, which is still the largest exporter of ivory in the EU, has managed to close down its own markets.”

The writer Hugh Fearnley-Whittingstall, who has campaigned against the ivory trade, commented: “It was a massive disappointment … that the Tories dropped their commitment to a ban on domestic ivory from their manifesto, and if that ban is now officially back on the agenda, that is excellent news.”

Johnson, alongside former foreign secretary William Hague and former environment secretary Owen Paterson, has in the past openly supported an all-out ban, which was a Conservative manifesto commitment in 2010 and 2015.

The UK has been accused of lagging behind other nations after China – the biggest market for ivory – announced it will close its market by the end of 2017.

Last year countries party to the Convention on the International Trade in Endangered Species (Cites) reached a landmark international agreement to shut down domestic ivory markets.

But there was no mention of ivory in this year’s Tory manifesto. It is believed the government came under pressure from the UK’s auction houses and antique dealers, who campaigned against a total ban. Currently the trade in ivory antiques (items produced before 1947) is permitted.

Animal rights campaigners believe laws to regulate the ivory trade are ineffective and perpetuate illicit sales, driving rhino and elephant poaching. As many as 20,000 elephants were killed for their tusks in 2015.

“Putting the interests of a tiny proportion of the UK antiques trade ahead of the interests of Africa’s elephants is unacceptable,” said Fearnley-Whittingstall. “These continued exports of both legal and illegal pieces from the UK make us complicit in the illegal trade of ivory and the continuing slaughter of Africa’s elephants. If we want to claim to be leaders in conservation, and the fight against the illegal wildlife trade, then we need to show solidarity with the US and China, and indeed France, who are in the process of wrapping up their domestic ivory trades once and for all.”

Action for Elephants’ Denise Dresner said: “Modern (illegal) ivory is sold in the UK under the cover of the legal trade and such sales perpetuate the poaching of elephants. The government must decide whether it’s more important to bow to the self-serving interests of a small commercial sector - the antiques trade - or do everything in its power to save elephants from extinction in the wild.”