I realise that most people ask questions when problems arise but I thought this story of my first "live" plumbing job is worth telling.
I realise that I made a load of mistakes so feel free to rip the pish but here are the warts and all.

The stop cock had gone in a friends house, it wouldnt shut off the water. It is a 60s council house with 8 houses running of the one mains water stop on the street. So I thought Id freeze the pipe, cut it put a service valve on under the house, then put a stop cock on under the sink.

I froze the pipe and cut it, put a service valve on, however I was probably working too close to the plug and water started fizzing out. I went to tighten it and turned the nut the wrong way!!!!! It shot off, mains water spewing out everywhere. Amazingly it didnt penetrate the floor boards and the drainage was so good there was no pooling.
However I had no mains key (wheres the emoticon for muppet?). After much panicing, running about, phoning about (even had some help from a nice police lady) and knocking on doors someone had a key. I switched the mains off (in 8 houses). As an aside I didnt tell them to turn their boilers off, thankfully one of the neighbours did.

I put a stop cock on now. However, the compression seal didnt take. I tried again, same problem. This was late saturday by now, it was leaking but contained so I left it for the morning.
Straight up to BnQ for I cant remember what (probably some miracle) and randomly some guy started talking to me. I told him my problem and he said that the pipes, although the looked by eye 22mm, were probably old school metric. BINGO!!!
Long story short I got a 3/4" olive and the stop cock took. No leaks. Held over night with the top end free. Today I managed to bend the pipe (lovely 30 degree 30 degree bend) and connect another stop cock above the floor boards and hook the system up.

Lessons:
Plumbers never come out at the weekend.
Always have a mains key
Forget a service valve.
Always have both sets of olive just incase the pipes are old
Always start first thing in the morning incase you need to go to BnQ 100 times in one day
Be very very nice to your neighbours when you switch off their water with no warning!

The thing with mistakes to

1, learn from them

2, put them right properly

well done on both points

You're not the first, I can remember a certain heating engineer using a 22mm speedfit fitting to temporarily cap off a pipe that wasn't 22mm , luckily it popped off during a pressure test

(With water Scruff don't get all excited about air testing and speedfit )

I had a similar but bigger mistake mate, flooded the whole place out, broke a mains

Learned my lesson, one slip-up can turn into a nighmare and then you realise your limitations.

I did it on Friday evening in dec which didn't help

Had a similar thing the other day - taps needed fixing, simple job, but the house is 15th century and it looks like the plumbing is original!!

The stopcock was covered in rust and I just knew what would happen if I tried to use it!

The trick is to know your limits and know when to pass the job on.

Very true for a DIYer, its when it all goes wrong and a leak starts or a end blows off you realise that you're not capable of fixing it, missing a part or just not acting in time.

When I burst the mains I paniced as I destroyed it completey . It was lead and I should have known to squash it.

It was a good experience seeing my plumber fixing the burst pipe though. He had bashed the lead to temporarily stop the flow. He had everything ready, freezing kit / olives / nuts / stop ends. Did a trial run on an off piece as it was an 80 year old pipe .

One thing I was not happy about was that I called an emergency plumber and fat git just sat in his van saying he couldn't fix it as the communal stop cock to the building was broken. He sat there for hours which he tried to charge me for @ £200 per hour. I gave him nothing and he said that I should have told him to go when he wasn't needed. I certainly told him where to go! Got a letter from the company saying that they were taking me to small claims court. They backed down in the end as they knew that had no case!

I have been caught out several times like this when it almost ran away from me. Filling the rads and forgot to close off drain valve properly. Running around like a looney trying to find the key

Which firm was that John

Rico

can't remember Rico, just dialed directory enquiries and asked for the first emergency plumber in my area (north London). Seemed like a smallish firm, orange van, Thought it began with A... the guy had real attitute about him as if he was put out by the call so made me think he owned the company

Sounds like the firm began with AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAPlumbing