I would like to go long on OJ but the smallest lot size at IB is too big, especially with the leverage.

How can I access a smaller lot size?

A lot of the CME Group Products have mini contracts (Crude QM, Natty QG, Soybean XK, USDEUR M6E) that are quite liquid and some that barely trade at all (Gasoline/RBOB QU). Unfortunately I do not think that ICE US/NYBOT has any mini contracts at all. Since your in England you could try a CFD broker - not legal here in the States.

Thanks.
Interactive Brokers is a CFD broker?

I used FXCM in the past for smaller lots.

Commodities - FXCM Support
https://www.ig.com/au/commodities
https://www.hotforex.com/sv/en/trading-products/trading_commodities.html

HotForex has the widest section I could find with cotton/coffee and cocoa but none I found so far have Orange Juice.

Interestingly, I asked a similar question 5 years ago:
https://forums.babypips.com/t/like-fxcm-but-more-things-to-trade/55485

https://www.ig.com/uk/spread-betting
IGIndex have been around a long time. Spreadbetting is tax free in the UK.

matthew28 

https://www.ig.com/uk/spread-betting IGIndex have been around a long time. Spreadbetting is tax free in the UK.

Thanks. They have sugar but not much else:
https://www.ig.com/au/commodities