A Prime Minister differs from a President in the following ways:
1. A Prime Minister holds power as long as Parliament is happy with her/him.
2. A President is elected by the general public where a Prime Minister is the leader of the majoirty party in the House of Commons.
3. A Prime Minister holds office for six years or until his party holds a vote of "no confidence".
4. A President is elected every four years whereas a Parliamentary elections are held every five years.
5. A Prime Minister can be ousted by a vote of "no confidence" by her/his party's parlimentary ministers.