A rise in the number of people sleeping rough in London by almost a fifth on the same period last year has been described as “shameful”.

A total of 4,780 rough sleepers were seen on the capital’s streets between July and September, according to the latest Combined Homelessness and Information Network (Chain) statistics which described it as a record level.

This is an increase of 18% from 4,068 people in the same quarter last year and up 13% from 4,223 in the period between April and June this year.

Homelessness sector organisations have said that, while ministers in the new Government have “made some really promising commitments” around funding, the latest figures are “a stark reminder that we also need a coherent, long-term plan”.

The Budget, delivered on Wednesday, pledged that local authorities in England will be given £233 million of additional spending in 2025-26 to prevent homelessness, which the Treasury said will take total spending to £1 billion in 2025-26.

“This will help to prevent rises in the number of families in temporary accommodation and help to prevent rough sleeping,” the Budget document stated.

A day earlier, London Mayor Sadiq Khan announced a £4.8 million investment to support people previously sleeping rough, which he said will help them “access financial advice, apply for benefits and use public services to help them stay off the streets for good”.

The Chain data showed that new rough sleepers – of which there were 2,343 – accounted for 49% of all rough sleepers between July and September, while 14% of those recorded during that period were classed as living on the streets.

Rick Henderson, chief executive of Homeless Link, the national membership body for frontline homelessness services, said the figures “tell a story of a devastating number of people whose lives are damaged by rough sleeping, failed by systems and policies that are not fit for purpose”.

He added: “This shameful upward trend cannot be allowed to continue. The new Labour Government can and must act to put an end to rough sleeping.

“The Budget pledged additional funding for homelessness and rough sleeping over the next financial year, but we urgently need clarity on how this and existing funding will be allocated.”

Crisis chief executive Matt Downie said: “It’s shameful that so many people are being forced to sleep rough, taking refuge in doorways and seeking safety on night buses.”

He added: “Ministers have made some really promising commitments, including more money for councils and funding for new social and affordable homes, yet this latest data is a stark reminder that we also need a coherent, long-term plan.

“The UK Government should consult as soon as possible on its promised strategy for ending all forms of homelessness and demonstrate the political will that can fix this awful, broken system.”

Meanwhile, the Housing, Communities and Local Government (HCLG) Committee has launched an inquiry into the experiences of children and families in temporary accommodation – a form of homelessness – and consider how temporary housing could be improved.

Its first evidence session will be held on Tuesday.

Figures published in August showed a record high of more than 150,000 children living in temporary accommodation in England at the end of March.

A total of 117,450 households were in this situation at that point, some 74,530 of which were households with children.

Both are record highs, according to data published by the Ministry of Housing, Communities and Local Government (MHCLG).