I do not have China visa before. Could I get a Shenzhen VOA on a one-day trip to Shenzhen easily?

Hey, JL, you can get it easily.

I went to China Travel Services agent in Hong Kong for such enquiry. The officer told me that VOA for UK and US passport holders are not easy, and suggested me to apply for L visa in advance. The application must be accompanied with a Shenzhen hotel reservation that must be fully paid already, even if I do not plan to stay overnight. It costs me HKD1910 for the visa and HKD250 for the hotel (the cheapest hotel available).

Dear, from what I know, it's difficult for US citizens to get Shenzhen VOA, but I don't think it's as hard for UK citizens. Since Hong Kong is very near to Shenzhen, I think you can take a risk and go there without the entry permit. The worst result is to return to UK but it's not a big deal. Anyway, if you apply for it through agencies, you will spend a lot of money.