There is little need to link to it, as even the tabloids have noticed and have commented.
A country’s credit rating is based on its, well - credit worthiness. The worse it is the higher the interest rates it has to pay to borrow, a bit like people really. One of the reasons Greece and Italy are in such difficulties just now.
Put bluntly it’s ability to pay its debts. How safe it is to lend them cash. The world can be in little doubt that whatever else the UK is, unlike Greece, Italy, or even France for various reasons as an examples, about as safe a haven as it is possible to find in the current world economic climate.
The only real threat to the UK’s ability to pay its bills is probably the EU and the Euro crisis.
No one would really take such comments seriously, except this particular individual happens to be the governor of the Banque de France. A bank that is effectively, in turn, the glove puppet of the European Central Bank (ECB). It's main reason for existence these days being simply to implement the interest rate policy of the European System of Central Banks (ESCB).
Clearly M. Noyer is not fit for purpose as the figurehead of even a hollow shell of a bank and in a rational country would be removed from office.
Clearly we would also be foolish to expect anything other than , not necessarily entirely justified reflexive overweening pride and slightly irrational Franco centric behaviour from France.