European Union membership comes with a steep price: national sovereignty. Member states have already given the EU control over their criminal law and their air space. But the price is getting higher and may be too much for one member in particular—Britain.

The EU is now proposing the creation of a borderless “common European maritime space” for all members. This means the EU may rule members’ territorial waters.

The European Commission first suggested a common maritime space in a discussion document earlier this year. It is currently assessing reaction to the idea in preparation for drafting a formal proposal in 2007. If the plan is adopted, then crossing the English Channel would no longer be considered an international trip, since passengers would never leave EU waters.

For Britain this would be more than a loss of sovereignty—it would be the loss of a vital national symbol. It was Britain’s supremacy of the seas that catapulted the island nation into rulership of a world-spanning empire.

Control of the English Channel has been England’s greatest defense from European invasion. When Napoleon concentrated his Grande Armée of 400,000 troops along the Channel coast, he wrote to his admiral: “If we can be the masters of the narrows for six hours, we shall be masters of the world.” However, Britain maintained mastery of its waters, turning back not only the army of Napoleon, but also, later on, the Nazi armies of Hitler.

The EU has already challenged Britain’s maritime sovereignty by opening up Britain’s fishing zones to European rivals and by seeking to replace the historic “Red Ensign,” flown from merchant ships of Britain’s great empire since the 17th century, with the EU flag. Giving up the Channel and the Red Ensign would amount to Britain symbolically turning its back on its history and relinquishing the key to its security.

Britain already faces the prospect of a tremendous loss of national sovereignty if the EU constitution is ever ratified. The constitution would put Brussels in ultimate power over Britain: The EU would be able to conduct Britain’s foreign policy; make treaties on behalf of Britain; draw up laws dictating Britain’s workers’ social security and social protection rights; pass laws outlining investigative techniques British police must use; dictate how schools are run; and give Britain a supreme court in Brussels. Even the British monarchy would no longer be the guarantor of its constitution. In effect, Britain would cease to exist in all but name.

The British people face a dilemma. Will they allow their government to continue to give up Britain’s sovereignty to maintain its member status in the EU—or will they reject EU membership to preserve their common law, history and identity?