Any information welcome, preferred from an expert.

Answer
What consitutes an expert? If anyoe really knew what would happen then they certainly wouldn't be sitting here typing answers to questions to make you rich.

So, as a self confessed non-expert I'll give you my common sense approach to this.

Why have the shares fallen? Utter panic over fears that the whole bank will come apart. Why might it? Well it may be overextended in the sub-prime credit arena and therefore have lots of loans default and little or no underlying assets to sell to recoup money or this maybe a temporary cashflow crisis that they are in. Ripping deposits out is not, I don't believe going to collapse the bank in an uncontrolled way. Savers will come back because they have a good brand and some loyalty.

Points to note: The UK banking sector is pretty well regulated and big player like Northern Rock have well established and maintained liquidity ratios to maintain but it is all backed (their deposists at least) by the Bank of England. So are they likely to go under? Probably not I would think otherwise the whole UK financial sector is in for meltdown.

Markets panic not necessarily when big guys think it's turn turtle but when Joe Blow on the street gets the wibblies which is what I think has happened here. I would think that there are many serious investors licking their lips and who will start to buy up low priced shares either today or tomorrow. It may go lower but I predict that at this time next year they will be at 75% or more of their old share price before the bump.

Is Northern Rock a bad business? No, I don't think that it is.
Is it worth what is was trading at before last week? No I don't think that it is - I would apply a 20% discount to be safe but I undertand that it is down about 50% if not more so there is a really good upside to be had if I'm right.

Am I buying in? Sadly no as I don't actively trade UK stocks anymore directly I speculate in Forex instead. If I had a brokerage account live today and GBP10,000 to gamble then I think I would buy in and wait 6-12 months for the rebound.

Other banks that have been hit with the collaterol damage from this would also be a good investment for the medium term. Nothing has fundamentally changed in their worlds but people are running from the sector as a whole and are leaving good gains for guys with a bit of balls and their heads screwed on.

Added later: You see that the UK govt has stepped in to guarantee all deposits and they would only do that if there was little or no risk of collapse. The issue is with the credit market as a whole not just Northern Rock so they will rebound from this share dump quite soon (maybe not to 100% of old value but who cares if you buy towards the bottom?). it is just a media frenzy. They are now saying that a lower share price makes it an easier takeover target so it looks like a great time to buy. You know I might even do just that with a few grand just to prove myself correct and put my money where my mouth is.

Added following day: I just made 15% in one day. Bought at 274p yesterday and sold today at 315p.

Can a Currency Trader legally obtain the foreign money they had traded for in coin form and cross the border?

A Currency Trader is a person whom buys foreign currency as an investment hoping the price will change so the trader makes profit when the trader trades back currency again.

A Currency Trader is completely legal and the trading process is usually done electronically and not physically because it is quick and easier than collecting the trade physically.

My question is if being a Currency Trader, can i legally obtain my foreign money in 'coin' form (because the metal is reliable compared to an electronic number) and then cross the border back to the United States with the traded coins.

For example-
Lets say that I want to trade $1,000 USD for Canadian Currency but i want physical Nickels instead of electronic numbers.
I think that it sounds reasonable because a trade is a trade, and shouldn't matter if i want to spend the extra gas collecting the extra weight of $1000 worth of Canadian Nickels to take home or not.

Serious answers please. Thank you.

Answer
Yes, of course you can.

But - why would you?

Coins are subject to the same rules as paper money - "The government has made a promise to..."

The paper itself is worth NOTHING and a coin, of any valuation, even the Canadian toonie ($ 2.00) by itself may carry the metal value of one to two cents. There is no silver or gold in any coins in the world these days.

Coins are bulky and heavy. It costs a lot of money to ship coins about. Would it surprise you to know that it has been statistically proven that the vast majority of coins hardly ever, in their lifetime leave the city they were issued in. They just go round and round between your stores and the local bank office.

Any one is free to buy any foreign currency (up to $ 10,000 without filing a police report) and carry them around, or put them under any mattress as you see fit.

A problem is that you pay more, get a worse exchange rate, when dealing with paper money. All currency trading is done in computers, even if you change between to accounts in your own bank.

A Canadian nickel weighs 2.35 g. 4,000 nickels would weigh 9.4 kg (20.7 lbs) It contains 96 % steel, a little bit of nickel, zink and copper plating. With a total scrap value at 0.27 c/lb, you would have carried $ 5.27 worth of metal over the border.

Don't even think of trading in currencies. The sum of the GDP of the entire world is traded every 24 h, at the speed of the fastest computers mankind can design and build.

Are you better than that? To get the really, really scary facts, read this from NASDAC

http://www.nasdaq.com/investing/forex/how-a-24-hour-trading-market-joe.aspx