A British prime minister is an elected leader with very extensive practical powers while confidence of the House is maintained. The decisive restraint is often the governing party itself. If enough government MPs rebel, the ministry can lose votes and eventually confidence. A narrow majority therefore allows a comparatively small faction to curb or remove a powerful prime minister.
Notable Point · 1:49:08-1:50:04
Why a British prime minister's own party is the practical restraint
A prime minister can exercise wide authority while retaining confidence, but a small internal rebellion can erase the government's Commons majority.