Whitbread's Light Ale, brewed in the interwar years, was a low-gravity Dark Mild of about 1028º. Watered-down X Ale, really. Not the low-gravity bottled Pale Ale that a modern drinker would expect. Possibly. If they know what a Light Ale is. The stuff's so rare nowadays I suspect few under 30 have heard of it.
Then there's the Light Ale from Flowers. A type of bottled Light Mild. I suppose at least the colour was right.
"A NEW LIGHT ALE
Palex is an extra light mild ale introduced Flower and Sons, Ltd., of Stratford-on- Avon. It comes as a boon to all those who have been searching for the ideal drink—a drink which has just the right soft, creamy flavour that is good for the health, gloriously satisfying and thirst-quenching and, at the same time, as light as a feather. The appeal of Palex is as varied as it is assured. After work, after play for luncheon, in the evening at home or during the day there is no better, cheaper, or more satisfying drink. It has been brewed with special care to suit athletes, sportsmen and sportswomen. You can buy Palex in all Flower's houses or from licensed grocers. Bottles only (not on draught) at 3s. per dozen small, or 5s. 6d. per dozen large."
Cheltenham Chronicle - Saturday 27 May 1933, page 1.
"It has been brewed with special care to suit athletes, sportsmen and sportswomen." You wouldn't be allowed to say that in an advert today. How do you brew a beer to suit athletes? Is that more or less alcoholic? Heavily hopped? Lightly hopped? Just made up and stuck in an advert? The answer to one of those questions is "yes".
There's an impressive amount of bullshit in that advert. Or rather advertorial, because it isn't identified as an advert. How can a soft, creamy flavour be good for the health? I've never heard of the health-giving propertiews of a flavour before. You can see theat the label expands on the sporting theme.
Sadly, I don't have an analyses for the beer. I do have one for Light Bitter Ale from 1936. That was a slightly more expensive bottled beer, that cost 6s 6d per dozen large bottles. According to the Whitbread Gravity Book, that had an OG of 1041. So I'd guess that Palex was around 1037º. Or about normal Mild Ale strength for the period.