Nigel Farage has dismissed Sir Keir Starmer's "smash the gangs" policy with a brutal one-word putdown on why it will not stop Channel crossings.
More than 10,000 illegal migrants have made the perilous journey across the water from France since the Labour leader became Prime Minister on July 5.
On Monday alone, 65 migrants travelled across in two boats, pushing the provisional total for this year to 23,598.
Sir Keir plans to target the people smuggling gangs organising the dangerous trips across the Channel, believing this will help to solve the issue.
Home Secretary Yvette Cooper has announced a £75million investment to increase border security officers, along with hidden cameras and improved monitoring technology.
It is all part of a new Border Security Command charged with shutting down the criminals taking advantage of those looking for a new life in Britain.
But Mr Farage scorned Labour's strategy, claiming in a brutal one-word putdown that it would be nothing more than a game of "whac-a-mole", with new criminals replacing any who are caught.
Asking viewers on his GB News show whether Labour's plan would work, the Reform UK leader said: "I have to say I have no great confidence it will.
"Even if you do smash the gangs, the money these people can make is so great that others will come and fill their place.
"It's rather like whac-a-mole. I just don't believe it's going to work. I don't believe it can be done."
The money for the new Border Security Command is coming from cash saved by ditching the Rwanda deportation scheme.
Rishi Sunak's government sought to fly those arriving illegally by boats to Rwanda in a bid to deter people from coming to Britain - but Sir Keir scrapped it as soon as he got into power.
The problem of small boat crossings plagued the last Conservative government, but Labour's opponents say the problem will only get worse without the deportation threat as a deterence.
