There are certain things in life that can instantly propel you back to the relative safety of childhood. For us, the little spoiltykins that we were, it is a restaurant that we knew as the Entrecote. I think I’m correct in saying that today there are merely four of (what we call) “our” Entrecotes in France although – beware – there are many many pretenders littered across La Republique. The Entrecote, our Entrecote, is a busy and unfashionable restaurant, sitting on a leafy avenue in Toulouse. It is decorated with Scottish tartan wallpaper and adorned with inexhaustibly furious French waitresses, complete with large, serious and intelligent-looking businessmen chewing the cud over their three-course lunch: lettuce and walnut salad with a vinegar dressing, steak-frites with sauce and profiteroles with gallons of chantilly.

So far, so insignificant. Except for the sauce – the mention of which I just casually glided past. The sauce is the sauce of gods. It is one of the world’s best kept secrets – so well kept, in fact, that you probably haven’t even heard of it. But hearing it leads to tasting it, and tasting it will, I vow, lead to a lifetime of happiness.

For the Entrecote’s Secret Sauce is one of the most exquisite tastes known to mankind. Rich, buttery and unusual, it is unquestionably one of the best combination of flavours on the planet today.

Not only is the Secret Sauce one of the greatest secrets in culinary history, but it is also the subject of much debate, rendering the delicacy something of a myth or a legend. No one, except for the keeper of the keys (the Godillot family who own the enterprise, and have done since its conception in Paris in 1959) knows what the sauce is made of. But this hasn’t stopped people guessing. French newspaper Le Monde reported that chicken livers, fresh thyme, thyme flowers, full cream, white Dijon mustard and salt and pepper are behind the concoction. French restaurant critic Jean-Claude Ribaut attempted to dissect the ingredients under some sort of complicated chemical analysis that made no sense and ruined the magic. Wild guesses have been made involving anchovies and herbs and condiments and vegetables – but all to no avail.  I once came across a man who’d conducted a love affair with one of the waitresses in a fruitless quest to solve the mystery.

Therefore travelling back to my childhood, to the impenetrably blissful days of long lunches at the Entrecote, has been more difficult than one might think. (I make this spoiled pronouncement with self-awareness, gratitude, lucky me, etc etc.)

Until now. For the Hélène Godillot, of the Godillot Empire, is overseeing the expansion of the enterprise across London, with franchises in the capital’s Soho, Marylebone, Canary Wharf and the City. These aren’t new restaurants – the first opened in 2005 – but they will revolutionise your lunch or dinner. Sadly, the Entrecote (important: real name Relais de Venise) seems to have been rendered somewhat insignificant in the ever-expanding red meat market, the Hawksmoors and the Gauchos have got the monopoly.

Which is no bad thing. Because real foodies, who want to eat fast and eat well, can still do so without having to confront over-friendly servers who have a propensity to pontificate about the 48,000 different cuts of meat before producing a delicious but unremarkable chunk of steak. You won’t get that at the Relais de Venise! Oh no! Here you instead have three choices – rare, medium, or well-done.

The Relais de Venise is unutterably delicious. The fact that the Secret Sauce has made it across the channel is reason enough for a national day of celebration. It pains me to write it, but the atmosphere of the British franchise isn’t quite the same as the French counterpart (no hideous tartan wallpaper, the waitresses are friendly rather than sexily stern) but the food itself is completely sublime. And the sauce is just as delicious, just as secret, as ever it was in Toulouse thirty years ago.