Starmer's view of his post - Brexit "reset" - "gain upon gain then lead annihilated! " (3-3,4)
For me, the key to solving this was the word “annihilated”, which I took as an anagram hint. There aren’t many anagrams of “lead”, but one leaps out as being relevant to the arrangement that Starmer negotiated a month or two ago with the EU.
Then I had a vague recollection of how he described it at the time, Googled to refresh my memory, and wrote it in.