LONDON — Even loyal fans of the Gay Hussar, a restaurant favored for decades by London’s political left, will acknowledge its shortcomings.

Quite a few admit that those include the food.

Lawmakers from the opposition Labour Party are excited when taken to the Gay Hussar, said Kevin Maguire, associate editor of the left-leaning Daily Mirror and a regular diner, “but usually if they have never been there before.”

Many have, however, and Mr. Maguire said that when he invited one female politician for lunch here recently, she replied, “In that case, I’ll have a sandwich first.”

But now, the Gay Hussar is up for sale, and suddenly its supporters are legion. Around 160 politicians and journalists have banded together as the Goulash Cooperative to try to buy the place.