Are the UK government acting like a three year old?

This article from The Independent explains how we’re going to have to pay the £39billion divorce bill.

They had been arguing for ages this would not be needed, and now concede it will.

Is anyone else reminded how a three year old will argue against something and then has to accept the original edict?

https://www.independent.co.uk/news/uk/politics/brexit-divorce-bill-uk-pay-eu-trade-deal-talks-david-davis-suella-braverman-a8364841.html