Taj travels , Star tours, Hari Om travels are some of the ones I know about who provide European and other packages for Indian travellers.
I have travelled to France, Swiss and Germany with Star tours and they provide very good service at affordable prices.If you are keen on having Indian ambience around you and are worried about food and safety then I would suggest these tours as most of the time the accomodation is at very good
[COLOR=green! important][COLOR=green! important]hotels[/color][/color] with lip smacking Indian Khana.The only disadavantage with these tours is that it gets very hectic at times with sight seeing and travel and you dont have the option of spending more time at any one place which you like and are hustled.
I am not sure of cheap flights from US to UK.They operate internally which means most of the tours start from London.
Hope this information helps you to plan your trip.
-Sabitha