Why would a tax stop speculation? All that will serve to do is enrich the government. That’s all that taxes do. And the government in Brussels is corrupt enough without this tax to underpin their misdeeds; not once in its existence has its auditors signed off on its budgets.
The only purpose for this tax is to undermine London’s financial sector. It has no other purpose.
It’s part of the cost of doing business. If the transaction fee makes each trade less profitable, there will be less short term, low profit trades.