From The Economist:

The two major parties are incompetent as well as divided. Their leaders, a charisma-free robot and a superannuated Marxist, are two of the most unimpressive in recent history. The cabinet and shadow cabinet are stuffed with hangers-on. Chris Grayling made a thorough hash of things as justice secretary, only to be put in charge of transport, where he has made an even bigger mess. Leslie Rowse, a historian of Elizabethan England, argued that the basic rule of academic life was that second-raters would always appoint third-raters over first-raters. Rowse’s rule now applies to politics on both sides of the parliamentary aisle.

The result is a negative equilibrium. The government can get away with being useless because it faces a useless opposition, and vice versa. The political system is designed to hold regular tests of strength, as government ministers explain their policies to Parliament. But these tests of strength have turned into tests of weakness, as incompetent opposition spokesmen fail to hold incompetent ministers to account. It is notable that the only serious blow against a minister in recent months was struck by a backbencher, Yvette Cooper, who dispatched Amber Rudd, then home secretary, during a committee meeting.