For dinner today I cooked something that I thought was an old retro classic - something we all grew up with and knew and loved. I was under the impression that it was a dish that had been served for generations in homes all around Britain and was a staple of our Anglo-Saxon forefathers. Cod in parsley sauce.

Of course it was - we've been eating this for generations haven't we? My Grandma used to make this on Fridays when meat was still banned. Her Gran made it for waifs and strays in the workhouse and before her, hordes of Angles and Saxons fought over the recipe on the fields of Essex in the year 511 initiating the first and only true cod war*.

We've been eating this since the beginning of the British Empire - since the days of the Armada, The Boer wars and the Robot invasion of 2354.

But I think my memory may have been manipulated by some clever advertising chaps.

I have been programmed.

I Googled cod in parsley sauce and couldn't find anything authentic. There were no old recipes for this 'classic dish' - there are no end of new sites, all sponsored by somebody asking you to buy something (see the video of the guy who waves a knife around as though he is going to gut his audience and can't finish words, saying "approx" and "max" as though he is reading a recipe without actually processing it into English with his brain).

Give me a minute while I check Mrs Beeton........

If any British dish existed before 1859 then Mrs Beeton would have it - and it doesn't. There's no cod in parsley sauce, there is no parsley sauce at all. It never existed before 1859. I doubt it existed before 1975.

Oh - I have another book to check, this one from the 70's and it's a beast.

British Cookery, Edited by Lizzie Boyd (1976) is perhaps the most ponderous tome ever written on the food of the British people from this era. It's not a cookery book as such, more a dictionary of everything that was occurring in our islands at the time - and there is no cod in parsley sauce. There's a parsley and butter sauce, but no mention of cod. (I think this sauce was traditionally served in Éire with corned beef, not fish).

And this really gives the game away: The British Film Industry have a page detailing an advert for Findus Cod in Parsley Sauce. There are no details, no cast, crew, credits. It's cold and bare but it does tell us that whatever we are watching is new, completely new. The BFI don't do retro, they don't do remakes. They are the most elite, academic and specific film organisation in the world - if they mention you, you have done something new - and this was something new; a food product invented by a company, which the advertisers made us think was something we had always been eating.

Cod in Parsley sauce.

I always thought it was a classic dish. Somebody made me think that.

My mind has been manipulated.

It was an invention of the embryonic 1970s industrial food complex and the idea that it always existed has been implanted in my brain.

I started off to write a blog, slagging of the people who gave us little squares of fish in sauce which you boiled or microwaved in the bag, but ended up scaring myself about how easily I can be told what to think.

It has made me feel quite numb.

Dinner was tasty thought - well done Findus.

*Not like that phoney one in the 70's where Iceland tried to fish in its own territorial waters, before the British Navy shot at them, leading to Iceland threatening to ban NATO troops from its soil and Britain quickly giving in.