Adding a WMS overlay layer in the same projection as the map is again straightforward as Leaflet provides a tiled WMS layer.
We are adding the same local authority district layer from GeoServer as with the OL3 example.
Add the following to the bottom of leaflet.js
:
// -- Load GB disticts as a WMS layer --
var districtLayer = L.tileLayer.wms('http://osgis.astun.co.uk/geoserver/gwc/service/wms?', {
layers: 'osgb:district_borough_unitary_region',
tiled: true,
format: 'image/png',
transparent: true,
maxZoom: 14,
minZoom: 0,
continuousWorld: true
}).addTo(map);