I will be travelling to the USA after Christmas. What can I take in my on-board back pack?

Can I take camera, mobile phone, book, bottle water? What restrictions are there?

Yes, just don't take sharp objects.

First of all you need a one quart resealable food storage bag...no larger, no smaller unless you only need a small one. check with the TSA website. http://www.tsa.gov/311/index.shtm This has the latest information as to what you can carry and what can't be taken in your carry on.

Arriving in the US is no problem with any of those. If you're traveling within the US you can't bring the water bottle through security, but you can buy water within the secure area and take it on board. Here's the US Transportation Security Administration's website with their list of permitted and prohibited items: http://www.tsa.gov/travelers/airtravel/prohibited/permitted-prohibited-items.shtm
Here is our guide for packing for security alerts: http://www.mousetourstravels.com/travel-security-alert-packing-guide.html

Happy travels!
http://www.mousetourstravels.com

It's best to check with the airline you're flying with as each airline varies but especially as you are going to the US.

It depends on what country you are coming from as far as in the US you will be allowed to have your camera, phone, and book. The water will not be allowed in your carry on luggage. You can visits the TSA website http://www.tsa.gov/ they have the complete list of what you can and can not bring on the aircraft with you.

I know that the UK has very similar restrictions to the US as far as liquids, etc....

Hope this helps!