= Group I alkali ion, 0 $\leq$ x $\leq$ 1). Of these, the sodium bronze is the only compound that has been reported with $x=1$ [@12], however in the hexagonal system, all alkali ions (Li - Cs) have been intercalated to varying degrees [@90]. In the cubic system, even low levels of doping ($x<0.2$) cause a dramatic colour change, which has led to tungsten trioxide being used as a material in electrochromic windows [@200; @182; @142]. Bulk superconductivity has been observed at 2-3 K in Na$_{0.2}$WO$_3$ [@197]. In addition to electronic doping, tungsten trioxide can also exhibit electron-doping via the removal of oxygen, with similar colouration effects [@153]. However colouration and conduction are not strictly related, as the conductivity in a thin film of oxygen-deficient WO$_{3-x}$ is much lower than in a thin film of M$_x$WO$_3$ of the same colour [@169]. This indicates that the mechanism for mobility is not simply due to delocalised electrons or holes, but rather changes in the band structure near the Fermi level, which are different for the two types of material [@169; @365]. Recent work by our group has concentrated on developing organic-inorganic hybrid materials based on two-dimensional tungsten oxide sheets (formed by corner-shared 