It really isn't. We'd have to leave the ECHR, relinquish our agreement to abide by the Refugee Convention and repeal the relevant UK laws.
All of that is straightforward if any government with a decent majority has the balls to do it.
Then, start returning every single person who arrives by small boat.
The problem is gone almost overnight. Within days, the boats stop arriving. No longer is there any incentive for any would-be asylum seeker to pay thousands to get to the UK by small boat. It's really that simple. But so far, no government has been prepared to take the necessary steps, because although simple to do, it would cause significant domestic and international condemnation.