If you have a blocked outside drain Crystal Palace there are some things that can be done before calling the plumber in. Look at the drain and check if there is debris lying around it. Remove any debris and then lift the grate that is covering the drain.
You will need a small enough cup that will fit inside the access drain. Using the cup slowly bail the water from the drain. Once the water has been bailed, then carefully reach inside the drain. If there is any muck residing down there it will need pulled out and thrown away.
Now you are ready to pull out the garden hose. Make sure it is hooked up to a spigot. Grabbing the end of the hose, where the water comes out, slowly start pushing it down the drain. There is no reason for applying force. Once the hose stops you are ready to pack the hole.
The best thing for packing the hole where the hose is, are old sheets. If you have sheets that are used when doing projects in the home these would be perfect. Start packing the sheet down the hole and around the hose. Make sure it is done tightly so the water will be forced down the drain when turned on. When the sheet has been packed in grab a broom and turn it upside down. Push on the sheet to verify it is packed in the drain really good.
Turn the water on and place your foot on top of the sheet. This helps to reassure the pressure will push anything through the drain so it will properly work again. With the water not being able to come out there is no choice, but the pressure to build and push.