SMSboy, a free online text messaging service, could become the latest victim of the UK mobile phone operators' plans to charge each other a fee for every text message sent to a rival network.

The future of free text messaging has come under doubt this week after operators revealed plans to introduce an interconnection charge of 3p for each cross-network text message from next month.

Yesterday, internet portal Lycos.co.uk, which allows users to send an unlimited number of text messages from a PC to a UK mobile phone free of charge, said it may be forced to withdraw the free service because of the extra charge.

SMSboy, which launched in November last year, lets users send text messages to mobile phones in the UK and Europe for free. Founder Shakil Khan said the company has called an emergency meeting today to assess the situation.

"We are very concerned over the future and we don't know what the solution will be," said Khan. "We send around 40,000 messages a day and the demand is certainly there, but the interconnection charges are going to put a lot of people out of the market."

Many of the companies offering free SMS facilities send the traffic via European networks, which offer lower charges than in the UK. At the moment SMSboy sends messages via Swisscom. It pays the Switzerland-based telecoms provider a small fee for each message, but the new interconnection charge will double that amount.

"The interconnection charges will stop the likes of us offering free SMS services," said Khan. "There are about five million users who send messages via free online services and they will be forced to use other services which charge. In the end there will be just a few big players cornering the market and the consumer will lose out."

However, mobile operators have said that the charge will not lead to a rise in the cost of sending a text message for their customers, which is usually around 10p. This is because they expect the charges to cancel each other out as messages are sent between operators.