Weirdest 'Cross-line' Issue?!

[#1]

I've just logged this so don't have a resolution yet, but just wanted to share with the community...
Noticing my speeds dropping off, I decided to login to my technicolor router to take a look everything was ok.  Imagine my surprise when I am greeted by a landing page for a BT home hub (on my ip of 192.168.1.254). So kind of confused I hit refresh and there was my technicolor landing page. Ok that was weird, refresh...back to this BT home hub! Looking at the landing page of this home hub I see my devices listed down below as connected via Ethernet, inc my iPad and iPhone which of course can't be as they are wifi! Weird, so I head over to speed test.net and sure enough I'm listed as having BT as my ISP and a completely different from normal public IP. Run a test and sure enough the speed is around 3 or 4 Mbps. So waiting a minute or two, hit refresh and boom, I'm back on plusnet with my old IP and I get a result of 45mpbs, much more like it!
Now, I'm definitely connected to my home wifi when this happens, and this also happens on an Ethernet connected PC, and even weirder is I can see this other home hub listing my devices as connected to it!  Now seriously, anyone ever heard of this and what da funk is going on, ha!
jim:green moderator note removed mod:end

[#2]

Update - ok lesson learned here..looks like my new neighbour is also using powerline, and neither of us had bothered to securely pair our adapters...sorry plusnet, not to do with you!  Fascinating one tho!

[#3]

Thanks for the update
I must admit that it is the 1^st I have heard that Powerline adapters in a neighbouring household can cause issue(s)
What Make / Model are your Powerline adapters ?
What Make / Model are your neighbours if they are different from yours
Are your neighbours Powerline adapters on the same wall as your
I am noting for reference in case I come across anything like this in the future

[#4]

Mine are netgear. I haven't got a clue what the neighbour has, I only figured this out half an hour ago, lying in bed and had one of those eurika moments so decided to switch off the powerline and hey presto everything started working again. I've powered mine back on and 'secured' them, I'm just guessing on the neighbour as he only moved in on Sunday and thinking about it that's when it all started happening!
Thinking about it, it's actually really lucky his homehub has the same IP as my router, if it didn't, i never would have seen his login page and I could have spent weeks trying to sort it out!
Will certainly have a chat tomorrow with him, take a look at his setup and also ask him to 'secure' his! Ha, all good fun!

[#5]

It is nice to have courteous & honest neighbours like your good self
Well done eureka moment for coming out the woodwork

[#6]

Just had this problem too.
http://community.plus.net/forum/index.php/topic,123641.0.html