Pretty sure that when I heard about central London south of the River Thames, say, 30 years ago … it was largely dismissed as a crime-ridden area with nothing to see. No need to go. Terra Incognito, down there.

Even the locals seemed to ignore it, although the area has been part of London for years now.

The areas of Southwark and Lambeth, two major chunks of the south-of-Thames bits off the city, were almost off the grid, in terms of transport.

Even now, an area that would be served by a dozen Underground stops on the “city” (north) side of the Thames parcels out exactly five tube stops in Southwark and Lambeth — Lambeth North, Waterloo, Southwark, Borough and London Bridge.

And why are we talking about this?

Because we have just now discovered that hotels in this part of London not only tend to be cheaper, they put the tourist within walking distance of many of the city’s top destinations.

In short, if you anticipate some dry weather, Southwark and Lambeth make key parts of London walk-able.

If you get out your map of London, it can be seen that Southwark and Lambeth lie south of London Bridge, in the east.

Across the Thames from the west of this thumb-shaped bit of land, via Westminster Bridge, are the attractions around Westminster Abbey, Big Ben, the houses of parliament, and the National Gallery. The Tate Museum is a short walk south.

Crossing the river via the Waterloo Bridge is Covent Garden, with plenty of playhouses, and nearby is Soho, with its long list of theaters and restaurants.

Within the bounds of Southwark are several leading destinations — Shakespeares’s Globe Theatre (saw it, loved it), the Tate Modern, over by Blackfriar’s Bridge; the National Theatre, the London Aquarium and the London Eye.

These are all walk-able from the middling hotels on the south side of the river. Maybe 20 minutes, if you are from a sensible, right-side drive country, look both ways on every street you cross.

This is good to know because London hotels are very expensive — about on the level with New York City hotels.

But if you poke around, you might be able to come up with something like the Day’s Hotel, right on the border of Southwark and Lambeth, for about $130 a night.

The Day’s Hotel is not new and the rooms are small. It is old and, as the Brits might say, a bit tatty.

But who goes to London to sleep? You stay out most of the day, and go to the hotel to shower and perhaps sleep.

More about Southwark’s somewhat seedy history: Because it was on the south side of the river it was outside the authority of London city, and Southwark was where Londoners went to partake of less-wholesome entertainment. Four hundred years ago, putting on plays was illegal, as was prostitution, in the main part of the season, and it thrived in Southwark.

It was also home to many of London’s infamous prisons, and to the underclass.

That is pretty much over now.

Bits of Southwark seem a little sketchy, but it is mostly gentrified, with small shops and ethnic restaurants and lots of residential towers going up.

For now, it has some hotel bargains, for those who are interested in walking to their favorite London destinations.