Its proposed financial transaction tax (31-page / 110KB PDF), which would be charged where financial instruments are traded between banks where at least one party is located in the EU, could raise €57 billion a year, the Commission said.
A spokesperson for the UK Treasury said that any such tax would have to be applied "globally", to prevent financial traders rerouting their transactions to countries outside the EU.
"The Government will continue to engage with its international partners on financial transaction taxes and has no objection to them in principle. But any financial transaction tax would have to apply globally and there are a number of practical issues that need to be worked through," the spokesperson said.
The tax would be applied to the exchange of financial instruments between banks and other financial institutions. These instruments include securities, bonds, shares and derivatives.
The Commission insisted only a "minimal" amount would be charged on 85% of the transactions which take place between financial institutions while leaving citizens and businesses who hold mortgages, loans or insurance contracts unaffected.
However John Christian, a tax specialist with Pinsent Masons, the law firm behind Out-Law.com, said that the "breathtaking" scope of the tax was such that consumers would likely see increased costs on routine financial transactions.
"The tax will be imposed on a wide range of transactions undertaken by others in the financial sector such as insurance companies and investment funds. The consumer will therefore ultimately bear the cost of taxes imposed on the routine management of their pension and investment funds - a point which is entirely lost in the presentation that it will only affect the banks," said Christian.
The Commission said that the financial sector is currently under-taxed in comparison with other areas. The VAT exemption on financial services allows banks to save approximately €18bn per year, it said.
Governments and European citizens have borne the cost of massive taxpayer-funded bailouts to support the financial sector. The 27 EU member states have committed €4.6 trillion to bail out the financial sector during the economic crisis, according to Commission figures.
Currently 10 member states have some form of financial transaction tax in place. The new proposals would "harmonise" these existing regimes, reducing competitive distortions in the single market and discouraging risky trading activities, the Commission said.
"The objective of the proposal could not be sufficiently achieved by the Member States acting by themselves," the Commission said.
Money raised from the tax would be shared between the EU and member states, the Commission said. States would also have the option to increase their share of the revenue by taxing financial transactions higher than the minimum rate.
Tax Commissioner Algirdas Semeta said the proposed tax would allow the EU to promote common rules for the introduction of a similar tax at a global level.
"Our project is sound and workable. I have no doubt this tax can deliver what EU citizens expect; a fair contribution from the financial sector. I am confident that our partners in the G20 will see their interest in following this path," he said.
The European Commission plans to present the proposal to the G20 Summit in November, it said.