The United States is set to begin giving visa applications from same-sex spouses the same preferential treatment granted to opposite-sex spouses.

Secretary of State John F. Kerry said on Friday that the policy change means a foreign citizen married to a US citizen can more easily obtain a US entry visa, and that applications from foreign same-sex married couples will be considered on a joint basis.

He said: “If you’re the spouse of a US citizen, your visa application will be treated equally. If you’re the spouse of a non-citizen, your visa application will be treated equally”.

Mr Kerry made the announcement in the consular section of the US Embassy in London, one of the largest in the world.

The England and Wales equal marriage bill was given Royal Assent in July, but the law will not take effect until next year.

“As long as a marriage has been performed in a jurisdiction that recognizes it, so that it is legal, then that marriage is valid under US immigration laws, and every married couple will be treated exactly the same,” Mr Kerry said.

He said that the change results from a review of State Department regulations following the Supreme Court’s overturning of the Defense of Marriage Act in June.

Previously, all applicants seeking to enter the US were considered on a case by case basis unless they were an opposite-sex married couple.

This was not the case for US citizens who married their foreign partners in states or countries where same-sex marriage is legal and then sought to bring their spouses to the United States to work or live.

Married same-sex couples from the 15 countries with national laws legalising same-sex marriage will be evaluated for visas together, as will same-sex applicants from states in Mexico that have legalised same-sex marriage.

Mexico, like the US, has legalised same-sex marriage only in some of its states.

The State Department said the new policy will apply equally at all 222 visa-processing posts worldwide, whether those posts are in countries that have legalised same-sex marriage or not.

In June, a New York City immigration judge immediately stopped the deportation of a gay Colombian man who is legally married to an American citizen just minutes after the Supreme Court struck down the Defense of Marriage Act.

In January it was revealed that plans laid out by President Barack Obama for immigration reform had included provisions for recognising same-sex families from different countries, and allowing visas for same-sex couples wishing to live in the US.