Better safe than sorry. My father probably just liked filling in the forms.

What form do we need to complete, one from the us or from the uk?

Sorted.

http://www.fincen.gov/fin105_cmir.pdf

GENERAL INSTRUCTIONS
This report is required by 31 U.S.C. 5316 and Treasury Department regulations (31 CFR 103).
WHO MUST FILE:
(1) Each person who physically transports, mails, or ships, or causes to be physically transported, mailed, or shipped currency or other monetary instruments in an aggregate amount exceeding $10,000 at one time from the United States to any place outside the United States or into the United States from any place outside the United States, and
(2) Each person who receives in the United States currency or other monetary instruments In an aggregate amount exceeding $10,000 at one time which have been transported, mailed, or shipped to the person from any place outside the United States.
A TRANSFER OF FUNDS THROUGH NORMAL BANKING PROCEDURES, WHICH
DOES NOT INVOLVE THE PHYSICAL TRANSPORTATION OF CURRENCY OR
MONETARY INSTRUMENTS, IS NOT REQUIRED TO BE REPORTED.

There's more loopholes in there for whomever wants to look.. explains what foreign (non US) banks need to do.

Cos the bank do it for you ..how kind ...

You don't need to complete any kind of form at all.

If it's cash your required to do the notification on your own, if it's through a bank, it's automatically done.

I transferred $40,000 from my UK bank to my husband's account here, does that mean he has to pay tax on it??

We've transfered a couple of chunks of money so far one under and one over $10k. Took no action other than telling my bank where to put it!!!

Does what mean that he has to pay tax? Simply transferring your own money into the country is not a taxable event.

I'm a UKC, he's a USC, I got scared for a second thinking maybe they would try to tax him on the money

On a slightly different tack... the Bank Secrecy Act requires US citizens and residents to declare ownership of overseas bank accounts, brokerage accounts, mutual funds, etc,etc, where the total value is over $10,000. The penalty for not doing so can be fines of up to $10,000 on a good day, the greater of $100,000 or 50% of the assets on a bad day, or a fine and time at the big house if they really don't like you (which for residents would no doubt be followed by a one-way trip home).

You have until 30June to tell them about last year.

This maybe a good time to invest in mattresses!

Does that mean if I have debts of over $10,000 that I don't tell them about they will give me money?

Fair's fair after all....