He caved in the side of the barrel with a single well-placed kick.
1955 June, “Notes and News: Locomotive Notes: London Midland Region”, in Railway Magazine, page 439:
It was to assist in the filling-in of the tunnel on the disused Patricroft-Clifton Junction line, which was the scene of a disaster in 1953 when part, below some houses in Swinton, caved in.
After he asked me a few times, I finally caved in and had a slice of cake.
2022 December 14, Christian Wolmar, “Productivity should play no part in pay negotiations”, in RAIL, number 972, page 46:
Eventually the NUR overplayed its hands with an all-out strike. And when Peter Parker, the then-chairman of BR, who was well regarded among his staff, called their bluff by threatening to close down the entire network, they caved in.