Treasury minister Liz Truss met with representatives of five libertarian groups during a recent visit to Washington DC that cost taxpayers more than £5000, Unearthed can reveal.

The groups include think tanks such as the Heritage Foundation and American Enterprise Institute, that aim to shrink the size of the US government and scrap environmental protections and which often fail to declare the sources of their donations

Truss also met with the American Legislative Exchange Council (ALEC), a controversial organisation that brings together corporate interests and state-level politicians to draft business-friendly legislation that is then enacted in state legislatures across the US.

A number of businesses, including Shell, BP and ExxonMobil, have withdrawn from ALEC in recent years due to its continued attacks on efforts to tackle climate change.

Truss further attended a roundtable with Americans for Tax Reform, an influential campaign to slash taxes that has strong links with the UK’s TaxPayers’ Alliance (TPA).

The TPA’s founder, Matthew Elliot, worked with Americans for Tax Reform early in his career before transplanting its model to the UK in 2004.