The ten year time frame is not a big surprise – trade agreements take a long time to negotiate, especially if they are detailed.
It is of course possible to knock something together in a much shorter time, but will it be worth the paper it is written on?
We also must not forget that the UK needs to negotiate two agreements – the first one is the agreement on the exit terms which will be triggered off by Article 50.
Article 50 only envisages taking account of a framework for future agreements. The second agreement would be the free trade agreement.
A transitional agreement would be sensible, especially as businesses both in the UK and in Europe will want to continue trading and surely politicians on both sides will see sense and make the process as smooth as possible.
A post-Brexit UK-EU trade deal might take 10 years to finalise and still fail, Britain's ambassador to the EU has privately told the government. The BBC understands Sir Ivan Rogers warned ministers that the European consensus was that a deal might not be done until the early to mid-2020s. He also cautioned that an agreement could be rejected ultimately by other EU members' national parliaments. PM Theresa May said she wanted Brexit to be "smooth and orderly".