Senior executives from Google and are due to give evidence to a parliamentary committee today on the issue of tax avoidance.

Both companies, along with a number of others in the technology field, have been accused in the media of not paying enough tax in relation to their sales and/or profits, although they all claim to work within existing UK tax rules.

Matt Brittin, the chief executive of Google UK, and Amazon's director of public policy Andrew Cecil, are scheduled to speak to the parliamentary public accounts committee, which is considering how multinationals are taxed.

Some of the criticism of large companies operating in the UK has taken the "moral" view of taxation, not whether those companies are actually breaking any rules.

There is a fear in some quarters that, if corporate tax rules are strengthened, companies under fire may scale back their operations here and move to countries with lower tax jurisdictions.

Others don't see why that should happen considering the UK is one of the biggest markets in Europe, which probably has to be directly served here.

Google UK reportedly paid just £6m in tax on sales of £395 million in 2011, while Amazon paid no corporation tax on £3.3bn in sales last year.

Facebook in the UK paid just £238,000 in tax last year, and Apple paid less than 2 percent in corporation tax on its profits outside the US, paying $713 million on foreign pre-tax profits of $36.8 billion. eBay paid only £1.2 million in tax in the UK.