It comes as officers from Scotland Yard now say that a man seen carrying a child by the McCanns' friend Jane Tanner was an innocent British holiday maker. They are focusing on another man with dark hair who was also seen with a little girl in his arms around 45 minutes later.
Investigators are using a number of e-fits, two of which are of the man who was seen carrying a child. Investigators are looking at a spate of break-ins in the area, one of which happened in the same week a year before Madeleine went missing, where a man got into a flat where young children were sleeping. During the show, the senior investigating officer, Detective Chief Inspector Andy Redwood, said two independent callers had put forward the same name for the man and another caller had given a name of a man who was known to be in Portugal at the time of Madeleine's disappearance. Mr McCann told the programme: "I think we're feeling hopeful and optimistic. "All along, we've said that a review needed done, and I think the Metropolitan Police have done a great job in piecing things together and bringing all the information, and really identifying new pieces of information that really are taking us further forward." His wife Kate said: "It doesn't matter how much heartache we put ourselves through, so long as we get the result that we need. "The Met have made huge progress and that's given us great hope that we can find Madeleine, that we can find out what's happened and bring us some answers. Madeleine's mother added: "Please, please have the courage and confidence to come forward now, and share that information with us, and you could unlock this whole case, so please. The general public have been so fantastic, but please stay with us and come forward." Mr McCann said people should find hope from recent cases in which abducted children had been found after long periods of time. "These cases can get solved," he said, "and I think that's what the public need to think about tonight, the new information, and really rack their brains and come forward, really." Asked if there was still hope they would find their daughter, Mr McCann said: "Absolutely, we don't know what's happened to Madeleine. We don't know who's taken her. "Probably our best chance of finding her is identifying that person, and that's why the e-fits and sketches and the new information tonight are so important to us, because that's probably the best chance we've got of finding Madeleine." Detectives investigating the abduction now believe the sighting of the man carrying the little girl is much more significant than previously thought and one of the main priorities for the investigation is to identify the man. Witnesses described him as white, aged between 20-40, with short brown hair, of medium build, medium height and clean-shaven. While police appealed for information on that suspect, they also ruled out a separate key sighting on the day Madeleine vanished. She vanished on May 3 2007 from a holiday apartment in Praia de Luz, Portugal, as her parents dined at a nearby tapas restaurant with friends.
DCI Redwood said: "Our focus in terms of understanding what happened on the night of May 3 has now given us a shift of emphasis. We are almost certain that the man seen by Jane Tanner is not Madeleine's abductor.
"It takes us through to a position at 10pm when we see another man who is walking towards the ocean, close by to the apartment, with a young child in his arms. This child is described as being about three to four years of age with blonde hair, possibly wearing pyjamas, and the man is a white man with dark hair.
"If this is you, and you are nothing to do with Madeleine's disappearance, then we really need to speak to you. It's so important for us to eliminate innocent sightings. But equally if anybody is looking at those e-fits and recognises the person, for whatever reason, then please have the courage to call in and tell us."
Investigators are also trying to identify fair-haired men seen near the apartment at the time who could be Dutch or German, and TV appeals will be run in Holland and Germany, although not Portugal.
Mr Redwood said: "There are one or two men who appear to be lurking around the apartments in the area itself. A consistent theme in the physical descriptions of those sightings is possibly blond or fair hair. So we are just asking the public quite simply, are these connected? But more importantly is this you? Because if it's innocent, then it's really important for us to take out those innocent sightings."
They are also looking at bogus charity collectors who were operating in the area at the time, and at a spate of burglaries that peaked in the month Madeleine went missing.
Mr Redwood added: "Whilst the numbers are low, we can see that there was an increase in burglary in Praia de Luz between January and April 2007 that spiked in April 2007. Windows were a feature, as well as burglaries taking place in the evening.
"We can see that in the week that Madeleine disappeared but in the year before in 2006, that two children were in an apartment when a man came in and he appears to have come through the patio door, had a look around inside and definitely had a look into one of the cots and then left without taking anything. Then one of the children raised the alarm.
"We're particularly interested in that event as to whether it has any resonance to the disappearance of Madeleine. The man was described as being a white man with dark hair."
On the day that Madeleine disappeared, there were four occasions where bogus charity collectors targeted properties in the area.
In the Crimewatch appeal, Mr Redwood said that Madeleine's disappearance could have been a planned abduction.
"Madeleine McCann's disappearance does, on one reading of the evidence, have the hallmarks of a pre-planned abduction that would undoubtedly have involved reconnaissance," he said.
Investigators are using a number of e-fits, two of which are of the man who was seen carrying a child.
The others are drawn from descriptions of men who were seen in the area around the time that Madeleine disappeared. Two are of fair-haired men who fit similar descriptions.
One is of a man who was seen twice by the same witness near the flat where the McCanns were staying. He was 30 to 35, thin, with short hair, shaving spots on his face and was wearing a black leather jacket. Another witness saw a similar-looking man in the resort.
There are also two e-fits of Portuguese men - one aged 40 to 45, who knocked on the door of the apartment where the McCanns were to stay on April 25 or 26 between 2.30pm and 3pm, saying that he was a charity collector.
The other, aged 25 to 30, approached a property on the Rua do Ramalhete, near the Ocean Club, at around 4pm on May 3.
There is a £20,000 reward for information leading to the arrest and prosecution of those responsible for Madeleine's disappearance.