Southend will become a city in honour of Sir David Amess, Boris Johnson has confirmed, paying tribute to the Tory MP who had been a long-time committed campaigner for his area to gain the status.

Amess had raised the issue almost weekly in the 38 years he served as a backbench MP before he was killed on Friday. On Monday the prime minister said the Queen had agreed Southend in Essex would be granted city status.

Johnson’s spokesman said that given the “exceptional circumstance” a recommendation had been made for Southend to become a city, which was immediately granted, although the formal certification will follow later.

“It is a very rare honour which Sir David campaigned passionately for,” he said. “He was a tireless champion of Southend, celebrating its achievements, the work of its residents and its thriving local businesses and diversity.”

Southend was one of several towns competing for city status as part of the Queen’s platinum jubilee celebrations in 2022.

On Monday afternoon, MPs packed into the House of Commons chamber to pay tribute to Amess, opened by the prime minister. Johnson said Amess had campaigned incessantly for Southend. “He never once witnessed any achievement by any resident of Southend that could not, somehow, be cited in his bid to secure city status for that distinguished town,” Johnson said.

The MP cited examples such as the world record for the most triangles being played at once; a group of stilt-walkers travelling non-stop from the Essex coast to Downing Street; and a visiting foreign dignitary allegedly flouting protocol by saying he liked Southend more than Cleethorpes.

“A compelling case,” Johnson said, announcing that the Queen had granted approval. “That Sir David spent almost 40 years in this house but not one day in ministerial office tells everything about where his priorities lay.

“He was not a man in awe of this chamber, nor a man who sought patronage or advancement. He simply wanted to serve the people of Essex, first in Basildon, then in Southend. And it was in the act of serving his constituents that he was so cruelly killed.”

The Labour leader, Keir Starmer, said he was “so pleased” at the announcement, saying: “It is a fitting tribute to Sir David’s hard work, it really is.”

City status is often associated with having a cathedral, a university or a large population but formally UK city status is granted by the monarch on the advice of ministers. Converting a town into a city does not entail new powers or tax breaks but is considered a marker of status by campaigners.