  We present the latest results from the UKQCD/RBC collaborations for the
K_{l3} form factor with 2+1 flavours of dynamical domain wall quarks.
Simulations are performed on 16^3x32x16 and 24^3x64x16 lattices with three
values of the light quark mass, allowing for an extrapolation to the chiral
limit. After interpolating to zero momentum transfer, we obtain the preliminary
result f_+^{K\pi}(0)=0.9680(16), which is in excellent agreement with an
earlier N_f=2 result.
