Why does this government hate workers so much? Yesterday, two of the richest men in European politics, the former Lazard banker Andrew Mitchell and the former oil trader Alan Duncan, sat side by side on the Commons front bench smirking with self-satisfaction as they announced a major assault on democratic trade unionism.

Tucked away at the end of a rambling statement about changes in Britain's overseas aid budget was a bombshell. The two millionaires said the UK would cut support to the International Labour Organisation. Britain will stay an ILO member, but the consistent cross-party financial support for the organisation's work has now been terminated.

The ILO cut is incoherent in Whitehall terms. In his speech in Kuwait and again in his statement in the Commons on Monday, David Cameron said he supported free association as a core right that Arabs rising in revolt against authoritarian rulers should enjoy. Freedom of association is at the very centre of ILO philosophy. The Mitchell-Duncan cuts seem, therefore, to contradict what Cameron called for – unless, of course, the Prime Minister did not understand what he was saying.

For Britain, it is a shameful and shaming act that out of the £8.4bn overseas development budget, there will be no money to support the development of workers' rights. Britain founded the ILO in 1919. In the 1920s and 1930s, the great Labour and union leader Ernest Bevin attended ILO meetings and used the organisation, which is based on tripartitite co-operation between governments, employers and unions, to nudge forward international conventions to outlaw child labour and protect seafarers' rights.

Roosevelt took the US into the ILO in the 1930s as part of seeking to lessen US isolationism when faced with the twin totalitarianisms of fascism and communism. Fast-forward to the 1970s and 1980s, and the ILO was the world forum where the suppression of Polish Solidarity was highlighted and rights of black workers in South Africa upheld. Workers striving for freedom in Brazil under Lula's trade union leaders, in China or in South Korea, were all able to find a voice and a hearing at the ILO.

The Tories have never forgiven the ILO for upholding the right of GCHQ workers to belong to a union. The first act of Tony Blair was to bring Britain into compliance with the ILO, though sadly the 1997-2010 Labour government never sent a cabinet minister to the ILO conference and had no policy to use the ILO to support Labour policy goals. But that is different from this new Tory ideological attack on workers' rights at a time when, in North Africa and elsewhere, free and independent trade unions are needed more than ever.

Underneath his smooth charm, Mitchell, the International Development Secretary, remains a High Tory millionaire banker, with all his class's dislike of trade unions and worker rights. It is a terrible signal to send to workers in Egypt, Tunisia, Libya, Bahrain and Yemen who need ILO help more than ever to put in place what the Prime Minister calls the building blocks of democracy. It is a victory for Lazard, where Mitchell made his millions, and a defeat for workers.

Labour and the TUC should highlight this attack on workers and unions and expose the shameful and shaming cynicism of this decision.

Denis MacShane is the MP for Rotherham and a former Europe minister.