LONDON, Dec 24 (Reuters) - Prime Minister Boris Johnson said on Thursday the trade deal struck with the European Union was not "cake-ist" but what the country needed, referring back to the bloc's accusations that Britain wanted to have its cake and eat it with an agreement.

Defending his trade deal, which will be dissected line by line by many Brexit supporters, Johnson said on one of the trickiest issues of the so-called level playing field fair competition guarantees that both sides could introduce tariffs if the either undercuts the other.

Johnson gave the example where if Britain raised welfare standards for pig farmers, it could make EU bacon cheaper: "We might under those circumstances consider imposing tariffs, I think it's highly unlikely, but we might."

He added: "I think we were told we couldn't have our cake and eat it and that kind of thing. I'm not going to claim that this is a cake-ist treaty, ... but it is I believe what the country needs at this time and the right way forward for the UK." (Reporting by Guy Faulconbridge and Elizabeth Piper; editing by William James)