At a time when other museums and galleries are either closing their doors to the great unwashed or at least trying to prise a few pound coins out of their hands to pass within their hallowed grounds – one is going the exact other way.

The Guildhall Art Gallery (unfortunately nicknamed GAG in their memos) and the associated Roman Amphitheatre remains in the basement have always charged admission, with the exception of Friday afternoons.

As of this week, it is now totally free of charge.

They are rehanging a lot of the paintings right now, so visits right now might miss a few things, but some new exhibitions will open shortly.

I think it is a rather worthy art gallery, with limited nods to modernity and a lightly austere layout, but it does have some interesting nooks and corners to discover, and of course, deep below everything is the Roman Amphitheatre.

Although the room it is housed in is fairly atmospheric – in a 1980s Tron sort of way – the Amphitheatre is not that impressive up close, and has lots of warning signs telling people not to touch the stones. You get a better appreciation of its size above ground though, as the perimeter is marked in the Guildhall forecourt paving.

If you want to see some rarer Roman remains, I’d try to get to one of the occasional tours of the Roman Wall Gatehouse organised by the Museum of London.

If you are visiting the Art Gallery though – I would strongly recommend also paying a visit to the Clock Museum on the other side of the courtyard. If you like that sort of thing, it is one of the best museums of its kind. Yes, it’s also free.

And finally…. every fan of London history should visit the Guildhall in a couple of weeks time for the bi-annual London Maze exhibition, with displays, talks and a chance to go inside the medieval Guildhall building itself.