I traveled to England the end of November early December for work (a 5 day conference). I also planned time for holiday both before and after. My work paid for the conference, travel between London & Cheltenham, hotel during conference and I paid for the international air fare. Can I claim any portion of the $1300, airfare from this trip?

If you travel outside the US primarily for business but spend some of your time on other activities, you generally cannot deduct all of your travel expenses. You can only deduct the business portion of your cost of getting to and from your destination. You must allocate the costs between your business and other activities to determine your deductible amount;
You do not have to allocate your travel expenses If your trip outside the US was primarily for business, you must allocate your travel time on a day-to-day basis between business days and nonbusiness days. The days you depart from and return to the US are both counted as days outside the US; Good documentation is an absolute must. SO IFyou travel outside the U.S. purely for business purposes, all your travel expenses of getting to and from your business destination are deductible. However, if you spend part of your time in a foreign country engaging in personal activities, you may have to allocate your travel expenses and only deduct the amounts allocated to business.