How bad is London traffic (Friday, 1pm in summer)?

IMHO I would do option B) and pick up/return the rental car to Swindon or ?. We drove all over GB in May 2011 but picked up and returned our car to Gatwick. I would much rather take trains, the underground, taxis or buses inside greater London, especially if you MUST catch a 3pm train. Transit is usually easier to time than traffic. I feel it IS the smarter thing to do.

I'm going to second the recommendation for option 2. I think it should be a goal of all UK travelers to avoid driving anywhere near London. And this is someone who loves to drive in the UK--just in the countryside though, thank you very much! Pam

I'll third that. In 2010, we stayed in Muswell Hill (North London) and the roads were really narrow until after we got outside the loop. This year, we're getting our car at Heathrow and heading west to Bath, the Cotswolds, and points west.

All on Board for Option B. Swindon is a great choice. Very close to the Cotswolds. From Swinnon it is an easy drive to a forgotten Cotswold village- fairford with probably the oldest and most impressive church stained glass in the entire area. Pretty little stream (and mill as i remember)

Its prejudice I'm sure but I dislike driving "south of the river". Nothing ever goes right. Also, Peckham would not be my choice of neighborhood. On the British Monopoly board, Old Kent Road is the first property, in the position held on the US one by Mediterranean Avenue. That area of London does frequently get into the papers with gang violence. It is by no means "practically down town". Its not Park Lane. There are some train stations there but no Underground. How will you get back and forth to the rental agency? There are many hire desks throughout the rest of London.
Swindon is an interesting choice. Have you heard of the Magic Roundabout? It is a "work of art". A huge gyratory system, it has two way traffic around a series of small roundabouts circling around a huge one. Seen from above it looks like a planetary gear box. Google it. Most people here go to Heathrow or Oxford to pick up cars for the Cotswold trips. You are not hiring a car at 10am and returning at 1pm the same day, are you? There is nowhere near enough time if so. If your can't miss train is a Eurostar remember you need a minimum 30 minute check in or you don't travel.

What Nigel said. I live "sarf" of the river about 8 miles south of Peckham and driving through London suburbs is no fun any time during the day. The question reminds me of the old joke when asking for directions and getting the answer "If it was me I wouldn't start from here".

Not to flog a dead horse, but - from today's Evening Standard: "An innocent bystander was shot after becoming caught in the middle of a feud between armed criminals in south London. The 30-year-old woman was waiting to be picked up after a shopping trip in Peckham yesterday when she was hit in the lower back by a single stray bullet. Her condition in hospital was described as stable. Detectives from the Trident Gang Crime Command appealed for witnesses to the shooting in daylight at about 5.15pm. Detective Inspector Ray Keating said the victim had been shopping in Rye Lane before walking into Bournemouth Road to wait for a lift home from her boyfriend. He said: "She was a completely innocent bystander who seems to have stumbled across what appears to be a fight between at least two men. One man pulled out a gun and fired a shot at the other man and unfortunately the woman has been hit. I am appealing to the many people who were in that area to come forward and speak to us if they saw anything suspicious or have any information." The suspects ran off separately, one of them possibly into Rye Lane. Police said no one had been arrested." = - =
You won't find me in Peckham...

I agree with everyone else....I would not return a car in London.
You could return it in Slough then take train into London, it's a 30 minute train ride into London.

Yep, second choice. Last summer, we were taking a bus from Victoria Station. We landed at Heathrow. The bus at Victoria Station left at 5:30. I had a reservation/ticket for the bus from Heathrow to Victoria Station, at 3:00. The person who directs patrons at Heathrow Bus terminal put us on a 1:00 bus. We barely made it. The traffic was really bad. The driver told us that it was like that all day, every day There was much road construction, etc. Would you believe 4 hours from Heathrow to Victoria Station! If you are on a schedule, the train, or Tube is the way to go. Even a cab could be bad with all the traffic.