More than 18,000 migrants have arrived in the UK after crossing the Channel so far this year.

Home Office data shows 661 people made the journey in 15 boats on Monday, the third highest daily total for 2023 to date.

This takes the provisional total for the year so far to 18,618, according to PA news agency analysis of the Government figures.

This is about 13% below the equivalent number at this point last year, when there had been more than 21,300 arrivals.

Last week 1,278 people made the journey, with crossings taking place on six out of seven days.

The highest daily total for 2023 so far was recorded on August 10 when 756 migrants made the crossing in 14 boats. The second highest number detected in a single day was 686 people in 13 boats on July 7.

Crossings continued on Tuesday. On August 22 last year a record 1,295 people were detected making the journey.

It comes as Prime Minister Rishi Sunak failed to guarantee he would be able to stop Channel crossings by the next general election, as he acknowledged the complexity of the issue.

At the same time the Institute for Public Policy Research (IPPR) think tank said the Government’s plans to tackle unauthorised migration risk creating a “perma-backlog”, with thousands of asylum seekers stuck “in limbo” and in need of accommodation.

Facing questions from broadcasters, the Prime Minister stressed his commitment to stopping the boats and said the number of migrants making the journey is “down for the first time in some years”.

But he said he would not be being “straight” with the public if he claimed the crisis could be solved overnight.

Meanwhile, campaigners are planning to send thousands of postcards to child asylum seekers after murals of cartoon characters at a migrant reception centre in Kent were painted over earlier this year.

Immigration minister Robert Jenrick came under fire for the decision, which featured characters including Mickey Mouse and Baloo from The Jungle Book.

He had reportedly felt they were too “welcoming”, although he told Parliament in July they were painted over because they were not “age appropriate” for the majority of the young people staying there.

The power of a simple postcard cannot be underestimated in brightening a child's day and conveying the message that they are seen and valued

Rima Amin, who started the Cartoons Not Cruelty campaign, said: “To say that the cartoons were not age appropriate fails to recognise the 9,300 under-14s that arrived in the UK just last year.

“That’s why we’re sending 9,300 postcards. The power of a simple postcard cannot be underestimated in brightening a child’s day and conveying the message that they are seen and valued.

“While we continue to call for the cartoons to be restored, we understand the immediate need to ensure that no child is deprived of a warm and compassionate welcome.”

The postcards, featuring flowers, love hearts and teddy bears, have been designed by members of the public and people are being encouraged to sign them online before they are distributed with the help of the Refugee Council.