Handing £55m to French authorities to clamp down on migrants crossing the Channel in small boats is “throwing good money after bad”, the home secretary has been told by a Conservative colleague as she was grilled by MPs.

Priti Patel revealed late on Tuesday that she had agreed to pay the sum as part of a deal with the French interior minister, Gérald Darmanin, to double the number of officers patrolling the French coast.

The announcement came after 430 people arrived on British shores in small boats on Monday, a record for a single day. A further 287 reached the UK on Tuesday, bringing the total for the year to at least 8,452, according to official data compiled by PA Media. More people, including children, were seen arriving on Wednesday.

Humanitarian organisations have said a strategy of interdiction will do nothing to address the causes of the Channel crossings, and have urged the government to create and enhance safe and legal routes to the UK for asylum seekers.

Appearing before the Commons home affairs select committee on Wednesday, Patel defended paying French authorities a further £55m as part of efforts to reduce the number of crossings, despite already paying France around £28m last year for the same purpose.

Tim Loughton, a Conservative member of the committee, said: “At the end of last year you made an agreement with the French to give them €31.4m to help with the prevention of the cross-Channel migrants coming in.

“We were told that money was going to be used for the doubling of the number of gendarmes, a suite of tech measures to improve detection, improvement to security infrastructure and provision of accommodation centres.

“Since that time, you now have a record number of boats which have come across the Channel, and the number of interceptions by the French has actually fallen.”

Referring to the most recent £55m instalment, he asked: “Isn’t that throwing good money after bad?”

Patel said: “This is an evolving situation, the numbers of migrants attempting these crossings from France has increased considerably.

“Our counterparts in France, our operational partners as well as our operational partners in the UK which involves our intelligence partners, have seen complete change in modus operandi in terms of the crossings.”

She said that instead of the majority of migrants coming from Calais, there was now a “widespread dispersal” of launches along the entire French coastline.

Loughton told Patel she was being “fobbed off with excuses” by the French authorities.

Paul Lincoln, the director general of Border Force, told the committee that the French authorities had made more than 2,100 interceptions in the Channel in the first six months of 2020, compared with 6,000 this year.

Border Force vessels and French warships were active again in the Dover Strait on Wednesday.

A toddler was seen crying as they were brought ashore in Dover, part of a group of people who arrived at the port on a Border Force patrol boat.

Immigration officials were seen helping a number of people on to the gangway and leading them up towards a white processing tent.

Despite the surge in such crossings, the UK continues to receive far fewer boat arrivals and asylum claims than many of its European counterparts.