Last week Madrid police searched Santander’s Spanish headquarters after suspicions were raised that the bank was linked to money laundering and tax evasion on the part of some of its clients. The Spanish authorities believe that up to €6bn has been hidden in 659 separate Spanish accounts. French magistrates raided Google’s Paris offices a few days earlier. Later this week the European parliament is set to give the green light to an investigation into the Panama Papers as well as a tough new package of measures to present to the EU finance ministers’ meeting on 19 June. Labour MEPs will be supporting both.

Across Europe, and in the European Union itself, action is being taken against the social scourge of tax avoidance and tax evasion. Persistent campaigning and well-timed whistleblowing has helped push what was once an obscure, technical issue up the political agenda. In the UK campaigners have fought for well over a decade to drag the activities of the tax dodgers into the spotlight, and I’ve supported them every step of the way, as a backbench MP and now on the front bench.

Labour’s Tax Transparency and Enforcement Programme, launched earlier this year, would stop the UK functioning as a hub of international avoidance and evasion. Some of the largest financial firms operating in the UK have been accused of complicity in tax avoidance operations. PwC, according the parliamentary public accounts committee, aided tax avoidance “on an industrial scale”. In 2013, Deloitte was accused by a charity of advising big businesses on avoiding tax in African countries – though in that case, the company claimed its advice was about investment potential, not avoidance. Ernst & Young act as tax advisers to Facebook, Apple, and Google. In March the Stagecoach group, advised by KPMG, had a tax avoidance schemes declared illegal by the high court.

We should be under no illusions about the scale of the problem. Reliable, conservative estimates suggest that at least $21tn is hidden globally in tax havens. Every dollar, pound or euro hidden means an extra squeeze on public services.

At a time when we have a government insisting on brutal spending cuts, it is a moral obscenity that major corporations and the super-rich should duck out of the obligations the rest of us fulfil. In the end, this corrodes the functioning of democracy itself. We can’t have one rule for the super-rich and one rule for the rest of us.

David Cameron at London’s anti-corruption summit on 12 May 2016. ‘Whether it’s Boris Johnson pretending to stand up to bankers, or Cameron pretending to stand up to tax dodgers, you can’t trust this government of the super-rich elite to deliver.’ Photograph: Facundo Arrizabalaga/EPA

The present Conservative leadership has sniffed the public opprobrium, and made something of a song and dance about its efforts to clamp down on evasion and avoidance. However, we need to judge David Cameron and George Osborne not on what they say, but on what they do.

International co-operation, particularly in the EU, is key to tackling avoidance. But while Osborne boasts in London of his determination to tackle avoidance, the chancellor has ordered Tory MEPs in Brussels to vote against anti-avoidance measures no fewer than six times in the last year. It was revealed in January that the government had been quietly lobbying the EU to remove Bermuda from a tax haven blacklist. The prime minister himself lobbied the European commission in 2013 for offshore trusts to be removed from new, tighter regulations.

The government has got into a nasty habit of saying one thing in public and then, once behind closed doors, doing quite another. It’s no wonder Tory peer, Lord Blencathra, described Cameron’s supposed crackdown on avoidance as a “purely political gesture”.

Whether it’s Boris Johnson pretending to stand up to bankers, or Cameron pretending to stand up to tax dodgers, you can’t trust this government of the super-rich elite to deliver.

That’s why Labour’s front bench will be giving its full support to an amendment to this year’s finance bill, supported by many backbench Labour MPs including Caroline Flint. This implements a key element of Labour’s Tax Transparency and Enforcement Programme by making sure that companies reporting on their overseas activities to HMRC will have this information made publicly available, instead of hidden behind HMRC’s walls as at present.

We’ll be demanding full, public, country-by-country reporting of multinational companies’ accounts so that they can no longer strike backroom deals with the tax authorities. Transparency is critical to ending tax evasion and avoidance. The government has the opportunity this week to finally make its deeds match its words – will they take it?