An oxy-fuel burner comprising: a central burner element comprising: a central conduit having a central axis and terminating in a central nozzle; and an annular conduit terminating in an annular nozzle surrounding and coaxial with the central conduit, the annular conduit 30) and the central conduit being separated by an annular wall; the central conduit being arranged to flow a first reactant and the annular conduit being arranged to flow a second reactant; a first staging conduit spaced apart from a side of the central burner element and terminating in a first staging nozzle; a second staging conduit spaced apart from an opposite side of the central burner element and terminating in a second staging nozzle; a first mechanism arranged to apportion a flow of the second reactant into a non-zero primary flow of the second reactant directed to the annular conduit and a non-zero secondary flow of the second reactant; wherein one of the first and second reactants (R1, R2) is a fuel and the other of the first and second reactants (R1, R2) is oxygen, characterized in that the oxy-fuel burner further comprises a second mechanism arranged to selectively apportion the secondary flow of the second reactant between the first staging conduit and the second staging conduit, wherein the first mechanism comprises a variable flow restriction to regulate the primary flow of the second reactant to the annular conduit, thereby indirectly regulating the secondary flow of the second reactant to the second mechanism in a complimentary manner, and wherein the second mechanism comprises a valve to selectively direct the flow of the second reactant between the first staging conduit and the second staging conduit. a central burner element comprising: a central conduit having a central axis and terminating in a central nozzle; and an annular conduit terminating in an annular nozzle surrounding and coaxial with the central conduit, the annular conduit 30) and the central conduit being separated by an annular wall; the central conduit being arranged to flow a first reactant and the annular conduit being arranged to flow a second reactant; a central conduit having a central axis and terminating in a central nozzle; and an annular conduit terminating in an annular nozzle surrounding and coaxial with the central conduit, the annular conduit 30) and the central conduit being separated by an annular wall; the central conduit being arranged to flow a first reactant and the annular conduit being arranged to flow a second reactant; a first staging conduit spaced apart from a side of the central burner element and terminating in a first staging nozzle; a second staging conduit spaced apart from an opposite side of the central burner element and terminating in a second staging nozzle; a first mechanism arranged to apportion a flow of the second reactant into a non-zero primary flow of the second reactant directed to the annular conduit and a non-zero secondary flow of the second reactant; wherein one of the first and second reactants (R1, R2) is a fuel and the other of the first and second reactants (R1, R2) is oxygen, characterized in that the oxy-fuel burner further comprises a second mechanism arranged to selectively apportion the secondary flow of the second reactant between the first staging conduit and the second staging conduit, wherein the first mechanism comprises a variable flow restriction to regulate the primary flow of the second reactant to the annular conduit, thereby indirectly regulating the secondary flow of the second reactant to the second mechanism in a complimentary manner, and wherein the second mechanism comprises a valve to selectively direct the flow of the second reactant between the first staging conduit and the second staging conduit.