The law that could leave News UK facing a billion plus fine, also applies to “…every person who shall publish or disperse, or assist in publishing or dispersing, any printed paper”. So Moya Greene, the boss of newly privatised Royal Mail has a very big problem this morning.

The only way the remaining copies of The Sun will be distributed today is if she instructs postal workers to break the law. I’ve emailed her first thing this morning to point out this rather obvious flaw in the current arrangements her company has with News UK.

But first, how have the extraordinary events of the last 72 hours come about?

I had pledged to take up the cause of anyone who wanted Royal Mail to listen to their demands – that they didn’t want a copy of The Sun delivered to their home – even if it was for free. On Wednesday, we launched a one page web site. After 12 hours of the web site going live, over 6000 people had enthusiastically responded.

Things were going well up until the point yesterday, when the cheeky spin doctors hoodwinked poor Ed into holding a promotional copy of the Sun.

Scouse friends with accompanying passionate vernacular said that we had scored an ‘own goal’.

It’s not easy being leader of the opposition. There is always a conga line of trouble waiting at your office door. You’re never far away from disagreement. And in those tiny moments of rest between the ennui of shadow cabinet meetings, there’s a helpful spin doctor who can press a promotional copy of The Sun into your hands.

I hope Ed managed to get home in time to have a beer and watch the Brazil game last night, if only to take himself away from from Twitter, overflowing with discommoded Labour party supporters, many of whom had spent the day sellotaping up their letterboxes.

Some campaigners even designed their own “Shun the Sun posters”. I’ve been sent pics of the free world cup promotional copy of The Sun lining budgie cages, cat litters and rabbit hutches. There have been the ceremonial burnings and bonfires, street recycling collections and the most popular of all, the ‘return to sender’ photographs of enthusiastic never to be Sun readers, posting back their unwanted newspapers to Wapping, courtesy of Rupert Murdoch’s Freepost address.

To be fair to Shane, the assistant to the head of public affairs at Royal Mail, he was doing his best. With only hours to spare, I had sent him a list of over 6000 names and addresses for whom delivering the Sun was an absolute no-no. Shane agreed that Royal Mail would use their “best endeavours” to respect the wishes of their customers.

By mid-morning on Thursday, the eagle-eyed blogger @brown_moses had noticed that contrary to the law, the Sun had failed to add an imprint (the name and address of the publisher and printer) to the 22 million copies of it’s promotional publication. On closer inspection of The Printer’s Imprint Act 1961, it appears that the statutory fine for failing to publish and imprint is £50 – per copy!

In spite of the risk of a £1 billion fine, the executives of the Sun chose to ignore their fiduciary duties to the shareholders and their veteran proprietor, Mr Murdoch and valiantly defied the law, giving the Attorney General a very big headache.

The Attorney General must of course, enforce the law. If he enforces the law, the Exchequer will be over £1 billion to the good. And The Sun will be no more. You can build a lot of new schools with £1 billion. So I am sure the Attorney General will do the right thing – enforce the law, and build the schools.

I watch with interest to see how the Attorney copes with this unusual act of illegality.

Meanwhile back in the furnace of the leader’s office, I hope Ed has a stern team talk with those cheeky monkeys in the press team over why he finds himself in an unnecessary embarrassing situation, again.

As any football fan will tell you, too many unforced errors ends in defeat.

As things stand this morning, I’m waiting for an urgent response from Moya Greene, to find out if she intends to risk her staff with a £50 fine for each copy of The Sun a postal worker delivers.

Tom Watson is the Labour MP for West Bromwich East