The countdown to the start of the 2012 Cooper Tires British Formula 3 International Series began in earnest today at Snetterton, venue for the first official collective test session of the year. It was also the first officially timed session for the all-new Dallara F312 chassis, nine of which were in action.First blood went to Carlin and Malaysian driver Jazeman Jaafar, who made the best of the steadily drying conditions to post an unmatched 1m 40.096s lap of Snetterton's '300' track layout - nine-tenths off last year's pole time - towards the end of the afternoon. Petronas-backed Jazeman's lap was a quarter-second quicker than that of his closest rival and top Brit, Racing Steps Foundation man Jack Harvey (Bassingham).In the much more damp morning session it was championship newcomer Carlos Sainz who led the way; with his father, multiple World Rally Champion Carlos Snr, watching from the pit wall, the 17-year-old Spaniard posted a best time three-tenths clear - again of Harvey. Sainz Jnr was a spectacular watch in the Red Bull Junior Team Dallara-Volkswagen, using all the track and beyond in his pursuit of top spot. Sainz ended his day fourth overall, behind Jaafar, Harvey and Pietro Fantin and nine-hundredths up on Carlin's fifth man, Harry Tincknell (Exeter).Though Carlin's men topped the timesheets there were wide smiles in the Fortec Motorsport pit, as today was the first time any of its four chassis had so much as turned a wheel. Fortec's fastest was championship newcomer Alex Lynn (Harlow), whose best lap was a bare second off Jaafar's despite the Carlin squad having had the luxury of a day's private shakedown at Pembrey last week."We are very pleased with our times," said Fortec chief engineer Mick Kouros. "This is our first time out and things have gone well. This game is all about good preparation, and we came here well prepared." All Fortec's Mercedes-powered F312s were within a second of each other. New team signing Hannes van Asseldonk enjoyed his first taste of the new Dallara: "I'm very pleased," said the Dutchman, despite missing some running with a clutch problem. "Everything is progressing well with the team."There were three Mugen Honda-powered National class chassis on track at Snetterton today - two T-Sport cars for Australian Formula Ford graduates Spike Goddard and Nick McBride, plus a CF Racing Dallara for Hywel Lloyd, the driver-turned-team-manager shaking down a hybrid chassis which will form the basis of CF's 2012 attack. McBride was enjoying his first taste of Formula 3 ahead of the expected debut next week of his Nissan-powered International class car; Nick's afternoon time was the quickest from T-Sport, with old hand Lloyd 0.6s ahead.There's a further full day of testing at Snetterton tomorrow ahead of next week's two-day programme at Rockingham - at which more teams and chassis are expected. The opening rounds of the 2012 Cooper Tires British Formula 3 International Series take place at Oulton Park 6/7 April.Cooper Tires British Formula 3 International SeriesOfficial test day 1 / Snetterton, Norfolk / 6 March 2012Leading International class runners am / pm (quickest time in bold)1 Jazeman JAAFAR / MAS, Carlin Dallara-Volkswagen 1m 44.970s / 1m 40.096s2 Jack HARVEY / GBR, Carlin Dallara-Volkswagen 1m 43.680s / 1m 40.347s3 Pietro FANTIN / BRA, Carlin Dallara-Volkswagen 1m 46.059s / 1m 40.377s4 Carlos SAINZ / ESP, Carlin Dallara-Volkswagen 1m 43.340s / 1m 40.476s5 Harry TINCKNELL / GBR, Carlin Dallara-Volkswagen 1m 45.236s / 1m 40.569s6 Alex LYNN / GBR, Fortec Dallara-Mercedes 1m 47.430s / 1m 41.170s7 Pipo DERANI / BRA, Fortec Dallara-Mercedes 1m 55.888s / 1m 41.285s8 Felix SERRALLES / PUR, Fortec Dallara-Mercedes 1m 46.472s / 1m 41.524s9 Hannes VAN ASSELDONK / NED, Fortec Dallara-Mercedes 1m 45.666s / 1m 42.132sNational class1 Hywel LLOYD / GBR, CF Racing Dallara-Mugen Honda 1m 46.743s / 1m 42.689s2 Nick McBRIDE / AUS, T-Sport Dallara-Mugen Honda 1m 51.545s / 1m 43.344s3 Spike GODDARD / AUS, T-Sport Dallara-Mugen Honda 1m 50.369s / 1m 44.891s