Tonight at about 6:30 I lost all Broadband connection both wireless and wired from my HomeHub 5 although my local home network was working wirelessly between my three devices.

It came back after a couple of hours but is now very slow although progressive speed tests, using BT's speed tester, have showed the speed gradually creeping up and it is now currently at around 3.98Mb download and is orange - it doesn't show the speed from the exchange, it shoud, I know, but doesn't, but it is green and says it is good.

I'm on BT Infinity 1 and usually get (a poor, I think) 22Mb download.

Any idea what could be causing this. I have changed nothing over the last several months on my network or phone line?

My devices are a Nexus 7 2013 running Lollipop 5, a desktop on Windows 8.1 and a Laptop on Windows Tech Preview 9879.

Your home network is entirely separate from the internet. It does not require any sort of connection to the internet to function. The fact that all devices wired or wireless lost the internet connection but could still communicate with each other over the local network shows that it was something on the WAN side of the router.

This could be the internal modem in the Hub 5 if it is plugged directly into the phone socket. Or the cable to the phone socket. If there is an external modem in addition to the Hub then it could be the cable between Hub and modem, the modem or the cable between modem and phone socket.

It could be the phone socket. But perhaps more likely is the phone line between your home and the cabinet out in the street.

There is only so much you can do on your side of the phone socket. You need to check the condition of the cabling to make sure there is no damage to it that might be the cause. Also check out any extension phone socket wiring as depending on how that is connected and the state it is in it can affect the broadband signals on the phone line.

When it happened did you check the phone? If so did you have dial tone and were there any crackles or other noise on the line? That could indicate a line fault.

If you can eliminate as far as possible your internal wiring and kit then the most likely cause
is the phone line or some Openreach plant associated with the Infinity service. That will mean getting BT involved to investigate and fix. But make sure you have checked your internal wiring/kit and are as certain as you can be that they are not responsible. If you don't and BT find out it is a dodgy extension for example you could well be looking at a three figure bill for the call out.

Thanks chrisjr

Found the line crackling so much as to be nearly unusable.

BT engineer came today (I wasn't put off by the £120 frightener) and found corrosion on a pole connection box a couple of hundred metres away.

All fixed and up and running normally again.

Not sure when but they seem to have changed the policy about the call out charge. I'm pretty sure that at one time they never warned you that you risked a £100+ call out charge if the fault was not on the BT network but your home installation. Now though they seem to be telling people in advance which I suppose is better than the bill landing on the doormat unannounced!

Have you been suffering loads of rain/snow recently? That certainly won't have done any outside cable junctions any good if they are not well sealed up. On the other hand I've seen Openreach guys up to their knees in water down manholes fishing out cables that have been working perfectly OK so water needn't be a problem if the job's done right

When ADSL first became available in my village and I was finally connected, I was only getting 1Mbit consistently when I was on 2Mbit. It wasn't congestion because even at 3am it was 1Mbit, and at that time I was likely one of only a handful of ADSL users on the exchange anyway.

They sent someone out who replaced a junction box and who I suspect had no real background in networking. The junction box did nothing of course, because the modem was synced at 2Mbit with no errors anyway, but the guy plugged in his BT laptop, ran a very simple test, and declared no fault found.

BT still tried to charge the call out fee even though there was very clearly a problem within their network. Miraculously, a month or two later, it fixed itself. As faults on BT's network seem to do.

Since then I just refuse to let BT send anyone out. In 10+ years of broadband I've never had a problem with the physical line, it's always been congestion within the exchange or something at the ISP.

To be honest I think the call centre lady said it may be £129 if the fault is found to be on my premises. The last time I called them in for a dead phone line they said the same so the policy isn't exactly new.

If, like me on both occasions, when something happens suddenly and not just after you've done something (accidentally cut a cable or something similar) then the fault is unlikely to be yours. I did a quick check from my nearest utility pole tracing the wire to my house to the various junction boxes and all seemed OK so I went ahead and made the call.

During the call the lady asked me to plug the phone in via the test socket inside the Openreach box - when I did this the box came off the wall because the Openreach engineer who had fitted the socket for my Infinity 1 about a year ago fitted it with just a wood screw (only one) into a plasterboard wall. I pointed this out as sloppy work by engineer so personally don't think I risked a charge, I would have argued the case anyway.

As regards the corrosion; the engineer said that when he took the cover off the connection box at the top of the pole a lot of insulation and corroded wire fell out so the problem looks like it may have been building for a while.

Had to laugh - when he came back to test the line after putting his ladders away and removing his pole climbing gear the line was dead - he then remembered the fuse block he'd removed before opening the connection box - and not replaced - so out came the pole climbing gear and ladders again - a really nice bloke and a job well done.

Thank you BT.

My connection sometimes drops for so long as well. I just wait until it's reconnected/synced and then start using the internet again. I never had this trouble when I was with BE, or BT's ADSL connection back in 2008-09.

I was with BE for years and would still be with them now if they hadn't sold out to Murdoch - it's my personal decision not to give any more of my hard earned to Murdoch than I can help.

I have nothing against Sky - I believe it to be quite good but I don't like Murdoch and I am sure my withholding cash from him really hurts him - not!