When you wiggle the lead, does the charging light on the laptop flicker? It could be the socket, as buteman says. It could also be a fractured wire within the rubber sheath around the plug from the adaptor. You should be able to work out which by careful flexing of the lead/plug.
"The power lead connection seems a little lose could this be the cause" - almost all of the time this is caused by the plug on the end of the charger which goes into the laptop and usually down to "wear and tear" - ie; due to unintentional pulling on the cable. If you establish that it is the charger cable and it is a "straight" connector then a suitable replacement would be one with a 90degree connector.