Show of hands, a brief guide to levels.
Foundation - assessed using eyfs points 1-9 (no sub levels). They take a base reading on entry to school & expect dcs to make 4 points progress in the year. Haven't got it to hand at the mo but I think the expected level at the end of the yr is 7,(anyone else remember for sure?) which roughly equates to 1c (national curriculum level; which is the levels they use from yr1 on,) although they don't use the same criteria. Eyfs, assesses lots of different things, inluding art, social development, literacy, etc.
Ks1 (yr1 & 2). The national curriculum focuses on reading, writing & maths, (I've never actually had any info on my dcs levels in any other subjects). 2b is the expected level at the end of yr2, and 1b at the end of yr1. Each level is split in three (thirds). C- just working at that level, b- working securely within that level & a - working at the top of that level & close to the next. They do SATS (exams) at the end of yr 2, but gradings are mostly based on teacher assessment.
Ks2 - (yr3-6). Progress is expected to be a bit slower (2 levels over the 4 yes) & the national expectation is 4b at the end of yr6. Compulsory SATS are at the end of yr6.
Hope that helps a little. For info on the types of targets within each level, have a look at blackeyedsusan/santas useful websites thread.