The opening BSB free practice session got underway in dry conditions before rain hit the 2.3 mile Thruxton circuit, meaning the riders who had completed a lap early on remained at the top of the times. 

Jackson set his best time just before the rain shower fell, while title favourites Christian Iddon and Jason O’Halloran were separated by just +0.033s in second and third. 

After a disappointing start to the season given his impressive pre-season tests, Kyle Ryde made a return to the top ten as he finished fourth quickest. 

Local man Tommy Bridewell was fifth fastest coming off his best weekend of the season at Brands Hatch. 

There was also a significant improvement in performance from SYNETIQ BMW rider Andrew Irwin who was sixth overall on day-one. 

Team-mate and championship contender Danny Buchan narrowly made his way into the top 12 with 11th place, however, Tarran Mackenzie - third in the standings - will need to go through Q1 after finishing 14th. Defending series champion Josh Brookes endured another tough day as he could only claim 19th spot. 

Speaking after FP2, Jackson said: "We definitely timed it right today; my crew chief this morning said these might be the only dry laps we get today and with that in the back of my mind, I went out and built up then it just seemed to click.

"I got into a good little run and it wasn’t the best lap I have ever done here, but it was good enough to be fastest. 

"The conditions did make it more difficult to get into a good rhythm because it kept changing from dry to wet in both of our sessions."

Given the conditions and limited track time on offer, Jackson believes many of the riders are still searching for a preferred setting heading into Saturday’s first of two race days.

"With the limited time we have had today with conditions really one way or the other; I think there are a lot of people still looking for the setting, unless they have something from 2019," added the FS-3 Kawasaki man.  

"The way it has gone this year, I don’t think you can write someone to be the race winner tomorrow.

"There will be a lot of hard work for everyone in the morning in the last practice, and then race one will be a game of cat and mouse, or people trying to hold people back, so we will see what we can do tomorrow."