I can think of examples of both!

The A12 at Brentwood and this alleyway in Clayhall went from unlit to lit (it's now lit with these but in post-top form).

The A40 Westway flyover through West London used to be lit with black flat-glass ZX3s on the central reservation but all the columns were chopped down to save energy in about 2008. To me, it was just a terrible waste of money, but I guess the energy savings have outweighed the installation and maintenance costs of the lights! The same happened to Hammersmith Flyover last year when it was widened.

So there you go, two examples of each! Anybody else know of any other examples?

The A27 at Farlington in Hampshire lost its lighting more than 5 years ago. Columns had been failing structurally for several years before (most) of them were removed.

Nearby, when the M27 was widened 5 years ago at Portsdown Hill, 18 columns were removed beyond the last one here.

The M27 originally had catenary lighting at J7, this was later replaced with conventional columns and the lighting extended to J8.

Both the M32 in Bristol and the M1 in Bedfordshire and Northamptonshire has had lighting removed.

The M4 had additional lighting added at the J19 for the M32 in the 1990s.

Ah, so it sounds as if the swapping between unlit and lit and vice versa is nothing new outside London then! But in London it seems to be quite a new thing - my four examples are the only cases in London I know of where there's been lighting added or removed.

I'm not too certain if there was any lighting, that were in use beyond junction 32a/33 of the M62. If there was its gone now, but a section of the M62 / A63 between junction 38 at South Cave and Hull has lighting, mostly near to Hull.

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From streetlighting to radio, dance through the night whilst the streetlights are glowing outside.

Nah, east of 33 the M62 has always been unlit - at least as far as the Ouse bridge.

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Another example. The old A30 at Honiton near Exeter airport used to be lit. When the bypass opened (which was unlit) in the late 1990s the old columns on the old road had their brackets chopped off but the columns remained.

Later on, as a business park was built, the lighting got put back.

Wow, full cut-off MRL6s on new columns on a dual carriageway? That makes a nice change! Shame the business park couldn't have been lit in such an interesting way! But the whole idea of reusing lanterns is uncommon anyway (although Redbridge are now reusing some replaced ZX3s and SGS203s to mass-replace SOX), especially in London - if it was London, LED lanterns would probably have been installed new, regardless of how new the lighting was.

Not quite sure what you are referring to...

The lighting that got put back is on the "old" road which is a single carriageway and they are Iridiums.

Oh OK! Sorry, I thought you meant that the original lanterns were kept in storage for several years and then reinstalled! I was referring to the MRL6s on the bypass, which I thought was what you were referring to!

It is more interesting than that. When the road opened between 1968 and 1970 it was unlit. Lighting was installed when the road was widened in the late 1970s to early 1980s, then removed in the mid 2000s. The current situation with lighting is therefore similar to the period 1976-1979, with lighting to both sides of a two mile section of unlit road.