I have two trips to Singapore coming up. My travel budget won't allow a business seat for both. After some jiggery pokery I have come up with a solution but am wondering if it will work.

The solution is to buy two tickets and combine them to give me one sector in economy and one in business on each trip:
- one economy return from LHR to SIN
- one business return from SIN to LHR

I leave LHR on the economy ticket and return from SIN on the business ticket. This still leaves the return leg of the economy ticket open.

I then use the return leg of the business ticket to get back to SIN and the return leg of the economy ticket to get back to LHR.

My question is - will I run into problems using the business ticket whilst I am in the middle of the economy ticket trip?