TCP seems better than UDP

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Been trying to work out why I'm getting such high pings of 30ms to the EU server from London, so I switched from UDP to TCP and now the ping is something like 3-7ms...

Various forums have said if I am making an RTS game I should be using UDP but after switching to TCP the lag is so much better between the computers, almost every unit in the game is synced up correctly, any thoughts on this?

Cheers
Rob