  Inclusive ep double differential cross sections for neutral current deep
inelastic scattering are measured with the H1 detector at HERA. The data were
taken with a lepton beam energy of 27.6 GeV and two proton beam energies of Ep
= 460 and 575 GeV corresponding to centre-of-mass energies of 225 and 252 GeV,
respectively. The measurements cover the region of 6.5 *10^{-4}<=x<= 0.65 for
35<=Q^2<=800 GeV^2 up to y = 0.85. The measurements are used together with
previously published H1 data at Ep = 920 GeV and lower Q2 data at Ep = 460, 575
and 920 GeV to extract the longitudinal proton structure function FL in the
region 1.5<=Q^2 <=800 GeV^2.
